I want my dad to be happy

So I am almost 14 (in 2 months) and i am worried about my dad and step mom. it is hard to explain my feelings. okay... so last Tuesday, it is Thursday, 9/11, my dad called me while he was at dialysis and asked my brother and I to make potato pancakes because we recently learned from our grandma. so i tell my brother and he comes into the kitchen with meand we start making them. our step mom comes in and tells us to get her all the ingredients and amounts written down, so we wrote as much as we knew. shw said, "how much milk, how many eggs, how much flour?" and my brother said "We just figure it out based on the amount of stuff in the bowl, that is just how we do it at our grandma's" and my step mom replies, "That's not how we do it here". I was kinda getting ticked off but decided to wait to see what was going to happen. she started doing as my brother instructed and was complaining and asking why we couldn't do it a different way every step of making them. at one point i asked, "so are we going to be doing anything, or are tou doing everything?" and she says "I'll do it". so i say "okay, i will just go take a shower. i called my dad and usually she takes her side, okay, always, he takes her side. he said he would "take care of it" and when i got out of the shower he told me that he told her he was only with her because of my little half sister who is 6, and that he couldn't even stand to look at her sometimes. she doesn't let my brother and i do a bunch of stuff because "we'll make a mess" an ld we clean everything everytime we use it, if we have cereal, no spills at all, she still says, "go clean up the table we don't live in a vacation house". i don't really like her, i have lnown her my whole life and she seems like a stranger to me. i wouldn't care if my dad divorced her to be honest. i just want him to be happy, but she makes me hate her so much sometimes, but the problem is, they haven't spoken since that happened and i don't want my dad to be unhappy if he were to get a divorce. i also feel horrible like this whole thing is my fault. sorry for such a long post, just tell me what you guys think