How to get over my worst heartbreak?

Hello, so me (22f) and my boyfriend (26m) just broke up last night, we’ve been together for about a year and a half. We got into an argument about a week ago and i left that night, we’ve been talking since but last night he officially broke up with me and blocked me. He’s the first serious relationship I’ve ever had and we got matching tattoos, lived together, and would talk about getting married and having kids (we even had names picked out). Our relationship was so amazing the first year but we started arguing a lot the past few months and it’s led to this. I truly want us to have a fresh start and try again but I know he went out to a few bars with his friend last night and i can’t help but think if he was talking to other girls and it’s driving me crazy. The thing is, he’s very attractive and has been with many many girls in the past. I checked his Instagram account about an hour ago and he has 3 new people he’s following but he’s private, it’s making me crazy thinking it’s other girls. Please leave me some advice on how to get over this breakup and how to not constantly think about him being with/ hooking up with someone else.