AITA?!

I’m not sure how to handle this. I have a deadbeat baby daddy whose a “sometimes” dad, my kids have grown to adapt to him being mostly out of their lives. 2021, he and his fling had a baby, they didn’t last and he and current girlfriend met and 2022 had their baby. The first child is disowned by him, his gf (the 2 BMs are literally close relatives) and everyone around them. Ours on the other hand, he claims to love, care for and miss BUT makes no effort in being active. They have seen him twice in the last year and a half. My kids found out 6 weeks after the birth that baby arrived when said GF contacted me for my kids to meet. They’ve ignored and never made an effort at all towards my kids AT ALL and now want them around, it doesn’t sit right by me! I’ve explained this to her but she thinks I’m jealous, petty, etc even though I left my abusive, narcissistic, BD for a reason. I’d never want to stop my kids from knowing their blood, they have usual contact and lovee the first sibling the dad disowned. In all of this, the “father” hasn’t said 1 word about it, GF says it’s my fault cause I’m stopping it yet I can’t stop a man who hasn’t even tried. I’ve always told him to be consistent or stay gone because our kids deserve more, he’s choice was to stay gone. He’s spoke to our kids on the phone and made no plans to have them around, yet his gf is coming at me for making it clear no one will pick and choose when my kids matter or not. My kids haven’t asked or mentioned meeting the baby either because they know they have hardly anything to do with them. Sorry for the long post, there’s so much more to it, just a whole lot of DISRESPECT given to innocent children that they expect to be swept under the rug and ignored because GF now has her own child to the DBBD.