Right, two things.
First, you didn't cheat. Honestly I've never seen the phrase 'emotional cheating' in a context that made me think it was actual cheating. It's overwhelmingly used by people who aren't secure enough about themselves or their relationships to understand that their other half can speak with members of the opposite sex, and even have feelings for them (because, lest we forget, that isn't something you can control) whilst remaining loyal. But here it looks like all you've done is talk to other guys without telling your boyfriend. And that is not, in any way at all, cheating.
Second, even if you did, there are major abuse red flags here. In the first instance, his insistence that you tell him when you speak to other men is controlling and is not acceptable. But it looks like he's then made it a condition of him staying with you that he gets to effectively treats you how he likes, both in terms of verbal abuse and controlling your behaviour. And all the while you don't see it because you think you should be grateful to him for staying with you, and feel that you need to make that up to him. But that isn't right at all. You have done nothing wrong, and it very much looks to me like you are the victim of his abusive behaviour.
The situation with his sister is irrelevant. I would break up with him and get as far away as you can. Then you can find someone who actually respects you.