Please credit me or link back to the original guide if you repost this anywhere :) Let me know if you want to translate it, too!

She is an option, but only in the epilogue. You need to flirt with her every given chance and stay single up until the Explorer ending where it mentions the two of you are together.

TL;DR version for those who wants quick answers. If I got anything wrong about the guide, please leave a comment to correct me and I will update accordingly.

Sexual Contents

• Yes: Tammy, Rex, Vace, Marz, Tang, Rex, Ane, Cal, Sym, Dys.
  
• No: Nomi.

Relationship Type

• Open relationship or Friends with Benefits or Hook-ups: Tang, Marz, Rex
  
• Locked monogamy: Dys, Cal, Tammy, Vace, Ane, Nomi (as in you're only dating them and no one else)
  
• Open monogamy: Sym, Tang, Marz, Rex (as in you can date them "only" but you can also date someone else)
  
• Possible polyamory options: Rex + Marz, Dys + Sym.

Note: Dys is an unique situation where you can only enter a polyamory with him if you weren't only dating him or Sym.

Break Up:

• If MC is a prolific parent: Ane
  
• If MC doesn't want kids: Cal
  
• Because the RO is not monogamous: Rex (will stay if you're in an open relationship)
  
• Because the relationship is unhealthy: Vace (both with and without therapy, but they stay together during colonial hero and astronaut ending)
  
• If MC becomes colonial hero: Ane, Cal, Dys, Sym.
  
• If MC is unable to prevent the plague: Almost everyone except Tammy, Nomi, and an open relationship Rex stays with MC. No mention of Cal.
  
• Always break up by default: Tang, Marz.

Children

• Does not want kids: Tang, Marz, Ane (Ane can have one to two kids with you if you want kids).
  
• Want kids: Cal, Tammy, Rex, Vace (won't have any with you because you two broke up before that)
  
• Fine with either or no mention: Dys.
  
• Like kids but don't have any of their own: Sym, Nomi,

Other Elements

• Cheating: Rex (you can cheat on Vace with him), Vace (he can cheat on Ane with you)
  
• Codependency: Dys

You need to break her up from Vace by convincing her that he's bad for her with 30 Empathy or Persuasion. Otherwise, if you saw him calling her names / propositioning you / being cruel to others, you can also use those as evidence to convince Anemone.

• Relationship: Monogamous

• Does not want children at all. Will leave you during prolific children ending but she will mother one of your child.
  
• Will leave you during Array ending (because of your association with her abusive ex) and during the virus ending (your relationship gets tense and stale).
  
• Has implied sexual content in her hangout scenes. She also mothers one to two of your children if you do want to have children but not a prolific parent.

Nem edition of this, you will need at least 90 Relationship with her to convince her to leave Vace. Otherwise, if you have higher relationship with him, refer to his section. You need to be in year 7 before she comes up to you with the scene where she vents about her relationship with Vace.

Use this situation to either confess to her and/or tell her that he's a scumbag. There are three evidences you can present without needing 30 Empathy or Persuasion. Otherwise, you need to be close friend with Vace to convince her with evidence. Refer to his section for the specifics of each evidence.

You will need to have enough (80) relationship points with Cal to confess your feeling to him during the same scene he asks you about Tammy. His relationship will begin around year 7 or 8.

• Relationship: Monogamous

• Wants many children. Will break up with you in the epilogue if you chose no children.
  
• Will break up with you during Array or Virus ending.
  
• Has implied sexual content in his hang out scenes.

You can proceed with his relationship normally or enter a polyamorous relationship with him between him and Sym.

• Relationship: Monogamous / Polyamorous*

• Has no preference on children. No mention of children in the epilogue, but if you're prolific parent, the children becomes a healing presence for him.
  
• Will leave during Array or Virus ending. Romance also ends if you let him join the Gardener.
  
• Has implied sexual content in his hangout scenes.

• For the alternative version where you and Dys are both in love with Sym, refer to Sym's section.
  
• (0) Date neither of them beforehand and preferably date no one to avoid complications.
  
• (1) You must let Dys go through with the bomb then find him at the ridge, if you have never done that, I included how to find him in my other gameplay guide since it's a bit lengthy.
  
• (2) If you have done everything right, there should be an option that implies they're together.
  
• (3) Pick the decision to tell Dys that he must come home then pick "Because I'm in love with you, Spacehead!" if you want a polyamory where both of you are in love, but he prefers Sym more.

(*) It can be a triangle where both of you loves Sym but not loving each other. There is also a variation where Dys loves both of you, but he favours Sym more. No perfect triangle where all three of you love each other.

You can trigger her romance by asking her out. From there, you can enter a polyamory between her and Rex.

• Relationship: Open Relationship / Polyamorous

• Does not want any children, this will be the reason for the break up in the epilogue if you're a prolific parent.
  
• Will always break up with you after a while in all of the endings. She continues a string of casual relationships.
  
• Has implied sexual contents in her hangout scenes.

You need to flirt with them and ask Nomi out during the scene where you find out about their crush on Rex. They can change their mind about Rex and enter a relationship with you.

• Relationship: Monogamous

• They become no parent on their own but do not mind your children.
  
• Will always stay with you no matter the ending.
  
• Has no sexual content, Nomi is demisexual and has yet to know if they want to do it. Implied they might get comfortable with it later on in the epilogue.

You will need to have enough (80) relationship points with Cal to tell him to back off from Tammy. Her romance will trigger late in the game, after she has her kid.

• Relationship: Monogamous

• Wants many children but is fine if you don't have any.
  
• Will stay with you no matter what afterwards.
  
• Has implied sexual content in her hang out scenes.

You can have a sexual relationship with her or start dating properly. Either way, Tang is not too committed on the whole relationship.

• Relationship: Open Relationship

• Does not want children at all.
  
• Will always break up with you in the epilogue no matter the outcome.
  
• Has implied sexual content in her hangout scenes.

Rex is pretty easy, if you have flirted before and unattached, he will make a move on you. You can enter an open-relationship polyamory with him and Marzipan.

• Relationship: Monogamous* / Open Relationship

• Wants many children, has many children of his own independent of you. If you're a prolific parent, you will have children together.
  
• Will always break up in the ending if you asked him to be exclusive, no matter the ending.
  
• Sexual contents near and far, sexual contents wherever you are.

(*) It counts as locked monogamy because you can ask him to not sleep around with anyone else but he tells you beforehand that it won't last for long.

Two ways to trigger his romance: Anger him until you get the ending where he wants to beat you ass and ask him to settle this another way OR confess during his heart-to-heart event where he talks about what he has done wrong with Rex and Anemone. There is another way to enter a relationship with him before that but I have yet to find it.

• Relationship: Monogamous*

• Wants many children, but you won't have any together.
  
• Because you will always break up with him in the epilogue, even if he had therapy. It's possible to have a good ending with him if you had the Astronaut career ending or the Disconnect the Array ending.
  
• ...You know he also has sexual contents.

There are multiple ways to approach this, I'll go with the ones you can do while having high relationships with him only here.

If you're here for the evidence to break him and Nem up, the evidence about his cruelty to others come from his fight with Rex from the scene before you confront him (Cruelty) while the other two are explained below.

You can get them to break up during the scene where you confront Vace about his behavior. This requires to have high relationship with Vace, at least 9 hearts I believe. Then, you need to tell him to break up with her.

You can choose "I'm in love with her" if you have flirted with Nem before. Then you need 40 Persuasion to convince him that he's out of her league, or you can say you can treat her better and use that evidence to tell her to break up with him later on. (Calling Nem names)

Otherwise, you can tell him that he can do better with 30 Persuasion. Or, you can tell him that you like him with a nifty 20 Persuasion and no self-respect... because then he'd ask you to be his side-piece, which you can also use as evidence against him. (Propositioning)

(*) You can also be his side-piece... like a clown.

You can trigger his romance by accepting his advance during expeditions, he's pretty full-on so you can't miss it. You can also enter a polyamorous relationship with him and Dys.

• Relationship: Monogamous* / Polyamorous

• Can't have children with you, but he likes children so he has no problem if you become a prolific parent.
  
• No mention of his romance in Array or Virus.
  
• Has implied sexual contents in his hangout scenes.

• For the alternative version where you and Sym are both in love with Dys, refer to Dys' section.
  
• (0) Date neither of them beforehand and preferably date no one to avoid complications.
  
• (1) You must let Dys go through with the bomb then find him at the ridge, if you have never done that, I included how to find him in my other gameplay guide since it's a bit lengthy.
  
• (2) If you have done everything right, there should be an option that implies they're together.
  
• (3) Talk to Sym and convince him to tell Dys to come home. You need at least 80 Relationship with Sym for this.
  
• (4) After you drag Dys home, you can begin a relationship with Sym through the naked scene.

(*) He's monogamous with you, as in he won't pursue Dys at all if you got to him first. However, you are open to date others as his romance won't lock you in.