A relationship is not supposed to hurt and cause pain, anger, stress etc. You shouldnt have to watch him like a spy or wonder can you trust him.
I wouldnt care how "great" he is. Hes cheating, lying, has no empathy for your feelings, no respect for you, he knows your a doormat and he knows you will let him get away with it which is y he keeps doing it..
He exited this relationship a long time ago and now your just easy sex to him. You only see him twice a week? Your a booty call. His heart has long left you..
You have two choices:
1. Stay and allow him to keep hurting you and making you more and more miserable, draining what little confidence you have out of you and laughing at you until he eventually leaves you for a woman who has more self respect or
2. Leavehim now, heal emotionally and move on-meet a good man who ticks all the boxes including trust. They do exist
look up co-dependency and get help for it. You are a doormat and nobody will respect you till you learn to respect yourself
"Don't ask a question if you can't handle the answer".