He wants him to be The Godfather, he ignores me!

Okay so let me start of by saying my husband and I lived at my in laws basement for 2 years while we saved up for our home. I cleaned downstairs and tried helping her a few times and she would say “no thank you” or one time I tried helping her cook and she replied with “if you do no one will want to eat” so after that I basically said “fuck you” in my head of course. My husbands middle brother brother was a complete asshoe to me! He called me all kinds of names anytime he passed by me “I would go upstairs at times for my MIL to see my daughter” at first I brushed it off but through time it got to me so whenever he called me a bitch I did too🤷🏻‍♀️ fast forward to now, 6 yrs later. He acts like nothing ever happened, never apologized and a few months back wouldn’t even say hi, now he says hi and tries being a bit more cordial. He has a gf whom he has a daughter and a baby boy with. They have the worse relationship, they beat on each other and she has even stabbed him once. My point is that they have no respect towards each other and don’t care each other into consideration. Well she had told me in the past that she wanted my husband and her sister to be her daughters godparents, that never happened. Now I had a party Saturday and just today my husband told me they asked him to be their boys godfather, keep in mind they asked him while I wasn’t even there making me believe they didn’t even take me into consideration at all! I’m guessing she wants the godmother to be her sister like she had stated in the past. My question is, would you be upset? I mean normally godparents are a married couple. I just feel like they went behind my back to ask him, I just picture him at church next to another girl, at every party when they call up the godparents and just ever major event for the kid. It’s not jealousy towards her but I am jealous that it won’t be me and I just find it so disrespectful of them. That’s something I won’t be able to experience with him like it should be. He already said yes because my husband is super naive but I can’t be okay with this, I am upset and I don’t know what to do

EDIT: I should’ve mentioned that all the churches around our area require godparents to be married so I don’t even know where they are thinking of doing it. Also, I am not jealous of him being with the girl. I’m not that psycho, my problem is with the brother always trying to go above me and asking my husband for shit behind my back, and I feel like this is a way to belittle me himself. I have talked to the girl before and she is extremely nice no so problem there

-to all saying they don’t have to be married, where I live they do. I baptized my daughter and went to about 4 churches around the area and all required godparents to be married. Also I’m not saying I wanted to be the godmother whatsoever. As I said, his brother has never been nice to me and even now we don’t talk, his gf is okay but she and I are also not bffs and she only speaks when she wants to. We see them maybe once ever 3 months IF that