Are you secretly disgusted by people who return to abusive (romantic) partners?

Nah. I think that going back is stupid, obviously. But it's understandable to go back to someone that has abused you. They manipulate your ass, gaslight you, and make you feel like you're the one that fucked up, that they'll change. But they never change. That's just something that a lot of people have to learn the hard way. No matter how much you pressure them, no matter how many times you try to get them to see that the relationship they're in isn't healthy, they won't listen. They'll always learn the hard way. Les gusta la mala vida deadass.

Edit: But I do have resentment for people that stay in abusive relationships with children. My mother is a survivor of domestic abuse, and she got out of it for my siblings and I. At some point, it doesn't matter how much you're willing to forgive, or how many times you're willing to try, or how much you believe they'll change. You have to do what's best for your children, not what you want to do because you believe things will be different. Staying can be fatal. You can make choices for yourself and go back, but you can't make that choice for your children. That's my opinion.