Toxic Ex; New Relationship

If someone has been in this situation I would love there advice! So,

I’m 20 and was with my ex for 4 years, on and off very toxic when it was good it was great when it was bad it was so bad! Anyway we figured that we drifted apart and thought we should fully end it which happened and it was beneficial on both parts like I said we were on and off and things were messy! Anyway, we live in different cities now and I finally moving on! I had this really great guy friend who I never thought anything of and we got on really well, until I noticed having feelings for him and thought wow, and we are together now! He treats me so so so good and I appreciate and respect him so much and I really like him, everything he is and I think it also helps because we have been friends for a while

Too! However, I can’t stop thinking about my ex, more of the memories and like even tho he didn’t treat me great I miss that familiarity. I feel very bad of thinking I miss him as I really don’t want too, and I’m so happy in my new relationship, I just don’t know what to do!!!!

Thank you xxx