XW had a baby yesterday...

[Coconut]

Ok, I went back and read some of your sitch, I'll give you my thoughts but not sure you are going to like it.

It seems like your kids are accepting the situation pretty well, they are young and feel like part of the family with ex and OM. They think of step-sisters as sisters and I didn't see anything that indicates that they are being mistreated by ex or OM. That is the perfect scenario for kids in this type of situation, much better than being ignored, abandoned or mistreated.

I think the biggest issue is with your inability to move forward (your thread is old so I don't know if your still stuck in the same place), your posts scream to me that you are using/wanting/expecting your kids to be your entire life. Your focus is/was solely on your ex and her new family, I didn't see anything about your "new" life other than activities with the kids (coach, volunteering at school, etc).

It's great that you are a involved dad, but are you happy as your own person as well?

My thought on how to handle the new 1/2 sibling remains the same as my original post. Be excited for them. You are their dad, that doesn't change, there is plenty of room in their heart to love everyone, and them doing so is what's best for the kids.

Be a great dad when you have them, work on finding your happiness and your own life when you don't.