My ex

So I have this ex and we dated for almost a year and I fell for him very hard. I was crushing on him for months before we starting dating and when we finally starting dating it was like a dream come true. Then we started having stupid fights and I got so tired of it that I broke up with him. But now it’s three months later and I still love him. I still can’t get him out of my head. But I sadly think he has moved on because he already had a new girlfriend. Any suggestions on what to do?? And advice for my situation??