Why do I always feel the need to control my boyfriend?

I am a 21 year old female and met my boyfriend at New Year this year. I love him very much and he loves me.

I find it very difficult to stop controlling him and often tell him not to go places with friends and feel paranoid and anxious if he is out with friends in case he meets someone else.

He would never cheat on me he has assured me of that however I just feel like I need to control him and keep him to myself which isn't me at all.

I haven't ever met a man like him and I've never been as serious with another man as I am with him and I think this may have something to do with it. I fear for our relationship if my behaviour carries on. Please send me your advice.