The only thing I can think of is an approach similar to mine, if the guilt is strong enough to stop you from going through with the act then you might want to focus your energy on finding a way to get a bit of distance between you and your family. Make it easier to properly isolate yourself a little bit and then the guilt should be a little bit less because you can tell yourself that they haven't seen you in so long so the pain will be less.
Of course, there will always be some pain there for them no matter what you do, I'm planning to write all my feelings in a big long format over a long period of time and then I'll just leave that for them to read when I finally do leave and it will be so long that they'll probably have finished crying by the time they finish reading it lol. Just going to get my own place, then keep my door locked for gradually longer periods of time and order all my groceries online, then disappear when my cats die and I've written everything I need to write.