Why do I care? Exs new baby

[TheLittleLion]

Some backstory: I left my ex when DS was 3 months old (he's now 2.5). It happened after DS and I stayed with my parents for a weekend, we returned home and discovered Ex had a few friends around for a party and there were condoms in our bed. Ex never admitted to cheating but after things that had previously happened it was just the last straw (emotional affairs, actual cheating and a few instances of DV). After we split I took DS over to visit his dad and he was violent to me (and drunk). After this he admitted to taking drugs and decided to move 200 miles away to be closer to his family.
Since he moved we haven't heard from him or his family at all. I am still friends with exs mother on Facebook (in case she want to see DS) and a few days ago she announced that he is having another baby.
For a reason that I can't quite fathom this really bothered me.. I just can't figure out why. I have no feelings for ex and am glad he is out of our lives and I know DS is better off without him but I can't stop thinking about it.
Has anyone been through something similar and have some insight?
TIA

[starry0ne]

I haven't been through similar however I would think your reaction would be natural... Not because you want him back but it somehow says your child wasn't good enough although likely hood is it will follow the same cycle.

[TheLittleLion]

I think you may have just hit the nail on the head. I think I'm worried how my son will feel in the future. His dad spent 3 months with him then never gave him a second thought, then went off and had another baby (whom he may or may not actually bring up). I don't want him thinking he wasn't good enough but somehow this new child is

[Bexpboro]

I left my ex of 15 years because of drugs and violence. I hoped it would shock him into changing & it did for a while, until he met someone else who shit-stirred and eventually created a massive wedge between ex, our daughter & me. He moved in with it, took care of her and her kid (not his) and didn't bother with our daughter....he then got it pregnant...broke my heart! Really struggled to deal with it and still do! I despise him but I look at our daughter and it hurts my heart that he doesn't bother with her 😔
I feel your pain, it will ease but I'm not sure it ever goes away. Big hugs xx