So SD12's actual birthday was yesterday.
I found out on Saturday, from BM, that DP gets the SDs on their actual birthday every other year if it falls out of the standard visitation schedule (we stopped by her party to drop a couple gifts off which was fine by me - I get along in a light, superficial way with BM as she's not crazy). BM reminded DP of the day.

I immediately said, "Great! You can take her out to a special father/daughter dinner since I'll be home too late to go." Bwahahaha.

So yesterday while on my way home, DP texts me and tells me where they are. Then invites me to "stop by and have a glass of wine" with him while SD12 has dessert and join them for the movie they are going to. What? And give up my quiet evening ALONE (my last one w/out DP or SDs for 10 days?!) heck no! I nicely said no thank you, but thank you. Ended up stopping by restaurant on my way to my car (I have a strange commute) said a quick "hello" and "happy birthday" and then left quickly.

Buh-bye.

SD12 had a good time with her Dad and DP had to be there for her alone for HOURS. Like a DAD.
Good for both of them and good for me.
Last year, I would have just joined them b/c I thought it would have been expected (like a "real" mom/dad) - but not any more.