I'm upset/irritated with my boyfriend for living with his ex-girlfriend
Why is he living with his ex?
The rent is cheap, he says.
Yeah, it's right for you to think this is weird. You should confront him, otherwise it's hard to build trust in this relationship.
I don't think it is going to work out. I think I'm going to move on soon.
I am sorry that you don't think it is going to work out. It is okay to be upset that your boyfriend is spending time with his ex and it is okay to not want it to continue.