5.5 year relationship ending after emotional affair

My (34m) ex gf (35f) had been together for over 5 yearz, 2 kids. We rushed into things. Honestly surprised we made it this far. Its been a toxic relationship. I wont go into the details but neither of us have felt loved or appreciated for the 5.5 years we were together. Both of us meant well but intent doesnt matter when impact is blah blah blah.

She had an emotional affair with her first baby daddy two weeks ago..she said it never went physical. They were in public all day at the mall with their daughter, so. Could be cope but I believe it. We had some talks and decided to work things out. Something ate at me so I checked her phone two days later. They were flirting, etc.

Not my proudest moment. I spiraled. No anger. Just pure heart break and humiliation. I couldnt stop debating with her and seeking reassurance. I was told for years not to worry about this guy.

Anyway. It all does not matter now. The relationship with her and I is over. Part of me is happy. This ending has been hell and the relationship was not much better.

This was my first and only serious relationship. Now I wont get to see my kids every day and all that.

Its just tough. I know many of you have been through similar. Just not sure how to proceed with life.