Should I ask my boyfriend to return the tv that he bought with his money ?
Is the TV not the one you wanted? Was it too expensive?
I think the tv is not worth that much money.
These days the biggest TV's are all the rage but if it cost too much then you have wasted money. He needs to be more careful in that regards so asking him to return it is a good idea. However, he did buy it with his own money so you might consider that just a tad here.
I'm starting to think you're not on my side.
I am on your side, but at least it wasn't your money is what I'm trying to get at. Then it would be not good.