My issue right now is that I don't feel like going to them when I don't have the kids during that particular weekend. I don't care to chit chat with her or even see her. I know these interactions are opportunities to show them who you are now and have no expectations.
It's tough and I can understand how you feel. There's up and down days. Having been at this for awhile, I can say the ups and downs are not as steep as they once were.
It's nice to go to the kids events, but missing a few is probably not a big deal and nothing that would effect your long-term relationship with them.