>My question is how do I know what the right decision is ? I don’t wanna regret it at the end. Any advice ?

Decide what you would regret more. There is no right decision, there's only the question of what is right for you.

In my opinion, sex is just sex: having a partner that is slightly more aesthetically pleasing doesn't make a big difference. That said, this is both my opinion and something I've learned through personal experience. Without wishing to sound callous, it may be possible that you can't learn this lesson unless you also learn it by experience. It may be the best path for you to throw away a functional relationship in search of a big booty, and then regret it, because then at least you know where your priorities are.

And so ultimately that's my advice to you: whatever it is you decide to do, make sure you learn from it.