I'm not going to comment much purely because this sounds like a completely biased post. I'd like to hear his side of things.
So errm, you cuddled and showed some sort of affection toward another guy whilst going out with someone else? First off, he has a right to be 'concerned' right now, if you are starting to develop feelings for someone else. It is baffling me that your a psychology student as well, what are they teaching people these days?
His reacting may have been OTT but he has a genuine right to be concerned - it is not as if he is totally wrong for being suspicious.
Without his side of things i cant offer any good advice, not to say that you are wrong in your post, but to say that you are not strictly in the right yourself.
In that regards, voice these concerns to your bf, he is the one with the concerns, he is the one you have to either convince that you are commited to relationship or not.
But one thing he is wrong to do is tell you that you cant see your friends, but hopefully (because of the Dan thing) you can see where he is coming from there. Compromise and talk to him! Hopefully by communicating you can find some middle ground to work from!