Relationship advice

I’ve been with my boyfriend for almost 5 years now. We have a daughter together. We’ve been through a lot in this relationship. He’s made me feel the most beautiful feelings but also made me feel the most horrible pain with some of the stuff that he has done to me.

Even through it all, he’s still my best friend. I feel comfortable with talking to him about anything but at the same time I feel like I withhold feelings and emotions from him and I let them build up.

We’ve been on a roller coaster here, after his last fuck up... he told me he was going to change and he’s asked me to marry him. Of course I say yes, but then I have days where I just lose it and have emotional break downs because of all the pent up emotions and pain. He has been good to me but I’m not sure if there’s things deeper than the surface. I don’t want to fuck up something that could potentially be my forever by bringing up old situations when I told him I forgave. It’s just that some situations come with pain and I don’t know how to go about it... i don’t know if I should release this relationship or I should fight harder for something I really truly love ?

And releasing this relationship will probably be the most hardest thing to ever do, I have never been successful with that.