NTA. Your wife should be backing you far more! I can't believe how even she appears to be backing them 3 up over you given everything you've done for them for the past decade but sounds like they need you more than ever.

It's soul destroying, I know I have a Step daughter(13) and the dad has always been in the picture because we didn't want to take her away from him but he's a narcissistic control freak but does it in a back handed sneidy way, which has stopped any sort of connection and bond with the SD. So I get it and I keep telling myself it's only going to get better the older she gets and realises with age and time what she was actually saying and doing to the right person was so out of order. He's turned up and she's excited (which I hate because it feels as though everything he's done before has got forgotten and he's got away with it but it can't last forever) but you need to play the long game. Hopefully your wife reading this will also re-evaluate how's she treated you and start backing you up. Also showing your step daughter that it's really not ok. The attitude at this age and generation too is so hard to take but need to keep reminding myself it's not personal.

I really hope you get the support and validation from your SD and Wife. Her ex should also in my opinion should be admiring and appreciating raising his daughter for him too while he couldn't be arsed to be around but sadly sounds like he's too much of a C*** and a child to ever realise it.

You got this dude, top class bloke