Just from your post it sounds like you might already have your answer. If he cheated several times with men, then perhaps that is your answer. He's trying to put it on you with excuses instead of being honest with you and himself about his sexual preferences.
Take care of yourself. It may take some time, but build a support system for yourself. Spend time with friends, family, church, find activities that you enjoy, volunteer, join a gym, do things just for you.
Find a therapist, that may help you sort through your feelings and clarity your choices.
It’s been hard for me also. But other way around I left in June. There are times I do miss him but my anger and resentment over take more of my emotions on a daily. It’s tough but I am learning each day is a healing process and I am in therapy also. I also turned to tarot cards and medium readings because I became desperate for wanting to know his next move in the divorce proceedings.