End it so she can heal without your constant nagging and guilt trips.

once you are comfortable being alone, you can be more particular about who you spend your energies on. Because you realize that you don’t actually need anyone. I was married for 24 years, the last 16 or so were very rough. After the divorce things improved exponentially. And now, I really only spend time with people who are good for me, because I have no problems being alone. I’m not in a position to tell you what to do, other than be comfortable, being alone. And if you Are still willing to deal with all of that, then absolutely keep going. if not, then it’s time to have an open and honest conversation with her.

you are right to watch out for your own needs too.

When you become less important to her than solvable problems, and this has been discussed with no changes, contact a divorce lawyer. Live is very, very brief.

Based on your post you have put in the effort and time. Time to stop investing in someone who leaves you feeling lonely, sad, frustrated and ignored. Life is much too short to chose misery. Find your sunshine and use this as a learning and growing experience. You did not fail.