Broken wisdom tooth, repairs don't last

[pigeonkisses]

I've lost part of my wisdom tooth a couple years back, it was fixed a few times. The entire cusp on the inside/front of the tooth is missing, and the dentist used three different fillings so far, all have come out, this will be the third time I need to go in three months. My dentist doesn't want to have it removed because it's not infected, but reconstruction doesn't seem to work. I am scared that extraction will be on the cards for me soon. Is there a solution that would work well for me longer term? Onlay? Or would that also come off? I am also a bruxer, so repairs have a lot to deal with.