How do I stay with him after everything he’s done?
On a very basic level, forgiveness is the answer. Keeping a record of wrongs, throwing his sin in his face, punishing him with a lack of love/respect because of his sin will quickly detonate any hope you have a beautiful, God-exalting relationship. “Forgive one another just as in Christ God forgave you.” (Eph. 4:32) On a deeper level, you probably need the help of a mature Christian friend, a qualified counselor, and/or a pastor who loves you both and can guide you with God’s Word.