Gain of custody/loss of sons

Since I have been without custody for so long, my kids are used to celebrating holidays with my ex's family.

I found out that now this extends to Father's Day.
She made them get up at 10AM to be at her Father's House so they could see him.

After letting my kids know that we had to go to dinner at 3pm, they called 2 hours late and asked where we should meet.
I had left about 1.5 hours after waiting, and it didn't bother anyone but me that being two hours late without calling might be a problem.

I have no reason to be here if my kids hardly care enough to show up for Father's day dinner.