What is going on here and what am I doing wrong?

[mvg]

Jumping right into this one, I'm just trying to figure out if I'm making a bunch of mistakes...

Last Wednesday, S5 had a baseball game (my night, my town, etc) and we were going into my weekend. After the game, S5 & S2 really like going for pizza and then to a new gelato place in town. S5 asked his mom if she'd come with us. S2 overheard and started essentially begging his mom to come with us. She said no. She said she was too busy to go and her excuse was that she had a communion party to go to on Saturday....yes four days from then. The excuse doesn't even make sense, it was for a kid of one of her friends. S2 got really upset and started crying. XW picked him up and walked him to the car as S5 started in on the invite again. Again, she said no, "too busy". I said, "Why don't you come get a slice with us, it'll take 20 minutes, you won't see the kids again until Tuesday." Again, no.

Fast forward to today, Sunday on my weekend. She hasn't seen the kids now for days and asks about getting together for breakfast. I couldn't do breakfast bc I took the kids to the zoo early but told her I was cooking at home tonight and she was more than welcome to come have dinner with us. She responded that she would be bringing her own dinner for herself and not be staying long (yes, you read that right) She didn't offer to bring anything for the boys, nothing. She got here 20 minutes late and didn't have anything with her. She sat at our dinner table and watched us eat. The boys asked her why she wasn't eating and she had the b***s to tell them, "Daddy only cooked for you guys, I'll eat my dinner tonight." I of course offered her a plate, as I cooked for about 10, she said no. The kids tried to get her to have a bit of theirs, she said no. Dinner took about 30 minutes. Afterwards the kids asked if they could play the Wii for a bit before bed, I said yes. She started to say goodbye and I was a bit confused. This is the same woman that blasts me every single chance she gets about how much she "loves her babies." I said, "Hey, the kids aren't going upstairs for showers for another 1/2 hour, you're more than welcome to stay and hang out with them."

Her reply, "I haven't even eaten dinner yet."

I didn't say anything and I guess that pissed her off bc she kissed them both on the head, didn't say anything, stormed out and let my screen door slam.

The kids didn't even look up, I'm not sure they even knew she left. That simultaneously comforts me and breaks my heart.

What the hell am I doing wrong here? I can't live like this.