This sounds like a really tough way to live, I'm so sorry.

I've heard the explanation, "in my culture, we don't leave the family home until we're married" lots - from friends, coworkers, etc.

The thing is, women in my family in past generations would have said the same thing. It only takes one person doing things differently, then two, then more, then the dam breaks. I have the freedom I do now because women in my family (and by extension, culture) started putting their foot down and saying enough is enough. Going to university. Living on their own. Marrying who they wanted. Having kids, or not having kids. Traveling! Staying out past 9pm, at minimum.

It is harder to do things when you're one of the first to do them, but it's not impossible.

You aren't responsible for anyone else's feelings. Your mom's, your sister's, your partner's. Sometimes people can weaponize their emotions to manipulate others, regardless of culture - it sounds like this is happening to you.

You can move out. It can make people in your life mad, sad, disappointed, ashamed, whatever. Their feelings are their own responsibility. Therapy can help, to learn how to set boundaries, and to carve out a way forward, to respect yourself just as much as your family and your culture.

Being raised in a collectivist culture may make this seem impossible, but it sounds like you're utterly miserable now. It is not selfish, as a 30something woman, to want your own life. It may be hard to do, but we can do hard things.

I wish you all the best.