I dont want the party. Alot of drama.

My bf, well ex has left. Literally. Since sunday he got mad and left the house leaving me and the kids alone. He hasnt call or texted. His mom was planning a batism party for our kids at the end of next month. Shs barely started planning it and nobody told me anything. His parents convinced him we had to batize the kids soon and she convinced him that she would pay for a party. A week later my ex told me about it and told me what she already had planned i was upset and kind of sad because she didn't bother to call or even ask what i had in mind or if i even wanted to do it this year. Me and my ex do not go to church so we werent in a rush . from this day on she never mention a single thing and the whole thing was going to be at her home. What bugs the crap out of me is that she doesnt see my kids at ALL we live 5 blocks away and has never called to check up on them see how they are or how i am. I know she doesnt like my family and at times i truly feel like she doesnt like me. Her and my mom got into it 2 years ago but i can tell she has never gotten over it. My parents have came to her house before for parties involving my daughters birthday or my baby shower and she never greets them. It upsets me that i never got the family in law of my dreams but it was okay because i thought i had the only person i needed, their son and my kids. The only person i gotten close with was her daughter who was going to be one of the godmoms. Well tmrrw we had the appointment for the class and we all have to go. I called her the other day and told her that her son left and i wanted to let her know in case god forbid he gets into trouble or something happens. I told her i couldnt afford the rent (because we were renting one of their house) and that i might have to leave. I was crying abit over the phone and i explained that i did talk to him because i knew where he was and he told me he wasnt coming back and we were done. He told me to figure out how to pay rent and the bills on my own. She didnt seem to care and asked "what about the party?" She was upset and said it was embarrassing if she had to cancel it. I told her well her son doesnt think about things like that and she said well we dont need him if he doesnt want to come thats okay but i already spend money on it and told everyone. I was in disbelief because who the hell is thinking of a party after everything that happen. The day he left he got into it with my parents and called my mom a bitch. I told this to his mom and she didnt comment on it she just said "well he was mad that she was pounding on the door so i understand him" i was so mad and told her thats no reason to call anyone a bitch specially your partners mother. My mom constantly brings us food and she might not be perfect but she only worried about me because of the bs he brings at times. The point being is why would my family go to a party where they arent liked or welcome. I always feel uncomfortable because i have asmall family and they are always on one side where everyone else is on the other. My friends and everyone i know thinks shes crazy because how will i want to show up in front of his aunts and uncles, cousins, etc after what her son is doing to me? I have been crying and its been so hard to take care of my 2 year old and 6 month old while working! Please tell me i am not being selfish. She told me i had to let her know, she said her son has done this before and will come back. I dont want him back im fucken tired emotionally and physically and been looking for a cheap place to stay and how to get to work and having my parents take care of the babies. I had enough that i already summited child support papers because i truly just want to move on. No one knows and i already know everyone will be shock that i did it because they know how much i loved him or wanted this to work. My question is how can i tell her i dont want this party?? I still want to baptize the babies but dont want her to throw the party. Exactly in what words can i say? The only reason i try to get along with her or be nice is because i know in the future when custody and visitation is set hes going to go back and live with her and my kids will be there with them 😞 i dont want her treating my kids mean or doing something out of spite. What should i do??