Paranoid

A

So my boyfriend- of almost a year, has gone out up town tonight with a couple of the lads and I feel so paranoid/anxious! He has reassured me all night that he only loves and wants to be with me and that he won't cheat. I don't think he'll cheat on me, yet I cant help thinking 'what if'. I've been so shitty with him all night since he told me he was going out which I know I shouldn't but I cant help it :( Any tips on how to deal with this???