AITA for not telling my ex's current girlfriend that he still calls me sporadically and tells me he loves me ?

I (26 F) dated this boy (27M) more than 4 years back. It was a toxic relationship to say the least and ended with him cheating on me, kinda ( I broke up with him for the umpteenth time after 1.5 yrs, because he'd talk to/flirt with and lead other women on. Two months into this break he slept with a girl I had an issue with - his current girlfriend, after making daily promises to be better, give me some space and win me back. I was DUMB, I know.)

Anyway, he keeps calling me every 3-4 months (I'm talking 100+ calls at a time, because his number is blocked) and I sometimes end up picking up when he calls from unknown nos. It's always the same thing on these calls, half assed apologies, gaslighting ( how he 'cheated' because I left him all alone) ,how he still loves me and how his current girlfriend is his karma for what he did to me and he doesn't really love her. Eventually they end up getting back everytime tho. I have always had half the heart to tell her what's been happening, but held back because a) this is the girl he cheated on me with - she knew us both. b) she knows of his behaviour pattern, his attention seeking tendancies and always forgives him and gets back. So I don't want to intervene and look like some psycho ex.

So AITA ?