Why do I feel this way?!

So my boyfriend has this friend that is single. His friend bounces from girl to girl. My boyfriend goes over there a lot to hang out.

Every time he’s over there, I always get this thought in my head that his friend is on dating websites trying to get my boyfriend to talk to other chicks.

My boyfriend has never cheated and I’ve been told by everyone that knows him that he’s not that type of guy. We’ve been together for 3 years and I trust him but I feel like my ex is the reason I constantly think the worst. Sometimes my boyfriends phone will go off at the ass crack of dawn so I wonder “who the hell is texting him this fucking early?” I fight the urge to sneak his phone because it’s not right and I’m supposed to trust him but I always wonder in the back of my mind if his friend is trying to hook him up with someone else or if some chick is texting him.

How do I stop these thoughts? I don’t want to just up and accuse my boyfriend of doing something he probably isn’t doing just because my ex fucked me up.