abusive ex boyfriend

I want advice on something i’ve been thinking on for awhile now.

I was with my ex almost 2 years ago now. he was mentally SO abusive and at times, physically as well. it’s something i’m still healing from mentally and has been so hard to find myself again and abstain a healthy mindset again.

i’ve thought about writing him a letting telling him the hurt he put me through, but letting him know i’m also thankful because he’s taught me what love is and isn’t. I feel like I just need to let everything out to completely heal. do y’all think this is a good idea, or what’s your thoughts???