1.
What's going on?: What's happening?
- It is very noisy in that room. What's going on?
- There are many police cars outside. What's going on?
2.
to get a divorce: to legally end a marriage
- Mark and Sally got a divorce.
- She wants to get a divorce, but her husband doesn't want to.
3.
to cheat on someone: to secretly be in a romantic relationship with a person who is not one's husband, wife, boyfriend, or girlfriend
- Tina and Mark got divorced because Tina was cheating on Mark.
- He cheats on his girlfriend a lot when he travels on business.