NTA.

I honestly can’t be mad at the 75/25 split on bills with the inheritance if she’s like my husband and doesn’t tap into it but for big expenses for him or us. We base how we pay bills based on income and his inheritance isn’t an income. That being said his inheritance is about 3 years of my salary so if we used it for bills it would be gone quick.

Now, the fact that she 1) didn’t mention it and 2) let you work overtime to pay all the bills when she could have helped is not ok.

I don’t know the structure of her inheritance but with my husbands, unless it’s a “true emergency” we have to give 60 days notice before a withdrawal but he also gets a lump sum every year. Doesn’t sound like that’s the case for hers.

I wouldn’t say she was selfish if she didn’t share with you but she should have told you and allowed you to restructure the agreement. I don’t think she’s an asshole if she doesn’t want to live off her inheritance for monthly bills but she should have told you that and allowed you to opt in or out.

I would dump her tbh.