This is where you blew it:
"Ok, about 3 months ago I moved in with my boyfriend and our wedding's booked for next year."
Over the past 30 years or so cohabitation prior to marriage became the norm in our society. However, the guy thinks, "Why by the cow when you can get the milk for free". Then they start lying, cheating etc. They feel then that they don't have to work for anything because it's all laid out on a silver platter for them.
What you need to do is to move out, and get your own place like today.
He only went with the proposal to con you into moving in with him. I would bet he's not paying all of the bills either.
I'm sure you are by now emotionally involved. That's going to take time to undo maybe some counseling for yourself as well.
You were very smart to watch for the red flags, and act on them. Follow through now, and always demand respect but also show respect for yourself.
Believe me you don't want to be looking over your shoulder checking cell records, and emails for the rest of you life.
You already have enough evidence to walk. Yeah, you catch 'em they admit it say they're sorry, and do it again. Kinda like a kid ya know? My jerk moved a drug addict into his house behind my back. I did not find out about it for 2 months. He said they were just friends, and there was nothing going on. She ended up committing suicide 10 months later in his house. I ditched him as soon as I found out. He had lied for years. I gave him many chances, but he's a proven loser.
I hope you now have moved out. You've had time since you asked the Q.