I'm so sorry that you have to deal with that.

Do try to stay though, for your kids. When you leave you give her the opportunity to tell your kids that you didn't stay, you're not interested, you are too busy for them, etc.

Don't give her that opportunity.

Instead, as best you can, sit in a spot where you can't see her. Then, keep your eyes on the game!

This will be difficult I know, but your kids will be glad that you are around.

I agree with Trippin: You can do this.