I’ll do no such thing; it is not selfish to need your own hobbies, goals, and sense of self to feel whole. It’s human. I’m actually really proud of you for admitting that “this blows” because I think so often we think we have to be stalwart heroes as moms—and this can be especially true for moms of disabled and/or neurodivergent kids. But it doesn’t make you any less of a loving parent to say that you don’t want that to be your whole identity.
It’s hard for me to offer practical suggestions without more information on your situation, but a few things come to mind. First, if you aren’t in any kind of support group, find one. It doesn’t need to be an in-person meet up if physically getting away is hard—there are lots of online groups on Facebook and other platforms that might offer a mix of empathy and tactical solutions.
If your unhappy marriage is obvious to your kids, I don’t think you are doing your kids any favors by continuing to set this example for them. You want them to grow into adults who love themselves enough to know they deserve happiness, and you want them to be partners who give those gifts to their spouses. It might be time for a very frank conversation with your husband.