Mintee, been there, done that. I spent years with the wrong bloke and was dissatisfied, and tbh felt like you do, and it all ended in tears, I vowed I would never put anyone through that again. Spent several years after that on my own having a good time. Now I have found a man I want to be with - no, I don't look anywhere else, I don't need to. I'm not influenced by what society says - I've found what I want, hell or high water.
The point you haven't mentioned is - is this other guy available, or is he going to wreck a partner's life too, if you too have fun together?