I also dislike cauliflower. Nasty stuff.
Yeah, sounds like poly is just not your bag. And that is totally ok. It shows up in threads here over and over that trying to be poly or trying to persuade a partner to be poly rarely works if they are not already so inclined.
However, that's a different issue than if you should stay in your relationship. There are folks who make mono/poly relationships work. But it is very, very hard. Search mono/poly and you will much to read and think about. You will need to decide if you can make the compromises necessary to be in a 'mixed' marriage. (And your partner will also need to make compromises too - it's not a one way street.) You will need to think about if you can live with and accept what being with a poly partner means. You've had some time to experience this - it's not brand new to you.
Keep in mind that if you decide that you ultimately want a mono partner, dating can still be humbling, hard on one's ego, and you will run into people behaving badly and getting away with it. Good luck - you are in a difficult situation.