How to end with a fuckboy

I’ve been seeing this guy for a month. I really liked him and the other night I slept with him. However, after, I heard tinder notifications and messages going off. He keeps following pretty girls on insta which are obviously matches... & he went to his home town at the weekend, he had a bag that he took and I found loads of condoms in there... don’t know if I’m just being a psycho as it’s early days but I don’t wanna get hurt by him - he’s making me insecure as he’s looking for more ! Wtf do I do??? I need to make him realise that he’s gonna lose me but I don’t know how