At what point do you break up a couple?

• Their traits don't gel.
  
• They don't spend time together.
  
• Things aren't moving forward, naturally.
  
• There is no woohoo.
  
• There is only woohoo.
  
• They want to woohoo with someone else.
  
• ARGUINGALLTHETIME.
  
• They're only in this relationship because Maxis.
  
• Their traits are the exact opposite.
  
• They're a serial romantic cheat.
  
• I begin to doubt why I/Maxis paired them.
  

I would also like if divorce was expanded upon when children are involved. Two main points; Child custody (shared or otherwise) and registered step-family within family trees.