Recent breakup, struggling

My boyfriend and I have been together for 3 years. I had a lot of unresolved issues when we met and I wasn’t faithful to him in the first year we were together. We broke up for a month, and then decided to work things through by me doing individual therapy and also couples counseling. Rebuilding trust has been tough, but I really felt recently like we were in a way better place. We were communicating better and working through issues better. All of a sudden, over a misunderstanding, he left abruptly. Broke up with me and said he can’t be with me anymore and hasn’t reached out in over a week. When he left he told me to let him go because this is final. I feel so sad about it. This hurts.