Am i going crazy??? Is this healthy?

I really don't think that this is normal :( i fantasize and daydream about my ex almost daily. I am in a relationship with a new guy whom i love but i find myself doing weird things like getting dressed up making myself look gorgeous and afterwards sitting down pretending i am talking to my ex smh i know it sounds creepy that is why i am scared. Last night i put on high heels walked up and down the hallway imagining he was there with his friends drooling over me. Sometimes when i am in bed i pretend i just made love to him and cuddle with my pillow pretending its him. I feel i dont want him anymore because he cheated on me and broke my heart but i am constantly daydreaming and fantasizing about him. When i see him in person i get butterflies but i deny his request to get back together because he really huirt me and i deserve better. Problem is i keep getting all dressed up and daydreaming while fantisizing he is drooling over me. It is scaring me because now i even imagine hhe is in my car while i am drivin