Getting back together

Is there any ways exs do get back together ? My boyfriend and I broke up a week ago ( he broke up with me out of nowhere)

I know exs are ex’s for a reason but I can’t help but feel like the reasons he gave are fixable if we work on them together.

Things like happiness, sexual intimacy and stuff.

I so badly want to fix things because when things were rough before we were able to sit talk and express our emotions and over come the barriers and now he has completely left without wanting to fix things.

Before we ended I did ask if he was seeing someone else and he did say no but I’m so heartbroken that I knew we had something so good and now it’s gone.

If he has told me how he was feeling when he began feeling that way we could have fixed it but he kept it all to himself and I feel like the problem as I didn’t know it was how he was feeling