Why did he do this with me?!!!?

It's hard to understand you and it was really long so I only read half of it. Yes you made a mistake, you're not the first woman to do it though. I don't know if you believe in Adam and Eve but she also committed a sin and was forgiven. There's nothing you can do now so just learn from it and move on. Next time, do not believe what guys tell you especially if they swear to Allah. That is a sin in itself.