Ok hun PLEASE READ THIS!!
If he doesnt trust you, this means he is INSECURE. It is not normal for him to tell you that you cant talk to people online, or facebook or whatever.
You are an adult and can do what you want. A nice secure boyfriend will know that you are not going to be cheating online cause you can have friends and chat with them and that perfectly normal.
If he feels he cant trust you, the only thing I can say is you have done something in the past to make him feel like that, and you tell him that it is NOT going to happen again. And that YOU LOVE HIM and nobody else.
Or if you havent ever in the past (which I am sure is the case), then tell him that; why cant you be allowed to chat with your friends, or go online if you want. Its not fair that he says you cant cant he thinks you are cheating. So jsut because he is insecure you have to feel bad about doing something that you ARE NOT EVEN DOING?
You need to tell him that if he loves you, and you are in a long term relationship that he HAS TO TRUST YOU.
And if he doesnt, then he needs to get over his insecurities.
I hope I helped a bit.