Am I a bad co parent?

I would really love everyone’s opinion cause apparently I’m awful & a horrible persons topping a father & child relationship between my kids and their dad.

I’ll try and keep it as simple as poss

We were together 6+ years.

2 children.

He is a drug addict. Cocaine & crack.

He would steal from me & the kids. Do drugs while the kids were in his care. Even went as far as to leave one child home alone in the middle of the night to go out and buy drugs with money he stole from my account ( I was in hospital with our youngest)

I didn’t know the extent until after I left him.

He was also very manipulative and horrible to me.

Relationship ends. I start new relationship as does he. He claims he is in a good place etc so I allow him to start having boys in the begining was with his mum at hers etc. Then he moves out of there so he has them independently. He takes 2 drugs tests both negative I continue allowing visits ( I KNOW I SHOULDVE STOPPED 😭 ) but he manipulates me and convinces me it was isolated jncidents etc. I know I’m stupid for that so I eventually wisen up.

I ask for a drug test he says no. So I refuse to let him have them as he won’t prove he’s clean ( I know he is not) he refuses to go to family mediation and just refuses anything other than me giving in and saying here have them.

I have tried saying have them at your mums etc.

Nothing. But he will text me every week and a half-ish complaining. But nothing gets resolved.

Am I being unreasonable?

I should add he hasn’t seen them for a couple months now because I refuse to put them at risk.

He just believes I am being hateful towards him and wants to stop the relationship. Mediation is a form/way of getting supervised visits/drug tests put in place but he is refusing. I am confident on stopping him having them, I know it’s right but he gets to me a lot ( master manipulator) and makes me feel terrible for it and doubt myself sometimes.

Also I do have residential custody.