Crazy ex stalker

Ok, I never thought in a million years I that I would have a stalker, let alone it being my ex. We were together for 3 years and I broke up with him because he cheated on me with two different women, (one being my ex-friend.) Ever since he's been trying to force his way back into my life. (I will admit, he gave me head like a month after we broke up and I guess now he thinks I want him back? - Mistake on my part.) He knows all of my favorite places to go, he sends flowers to my work almost every week, he blows up my social media account if I post pictures with another guy like he owns me or something. It's getting to be ridiculous but he hasn't posed a threat so I can't really go to the police... he hasn't put his hands on me or anything, it's all been verbal. I kinda feel bad for him because I could tell he really loved me, but now my love is tarnished and it will never be the same. I've moved on... what should I do?