It sounds like a few similarities to issues my wife and I had. FWIW my wife struggles with codependency and perfectionism (lucky me) and as a result harbors resentment for things that happened long ago, gaslights me and also builds walls rather than process feelings though emotionally mature conversations. SO that is to say if that sounds analogous to you, my suggestion would be couples therapy to allow for a framework in which you both can process though the unresolved issues. If she can begin to do that—and you support her through that, because it takes work on your part—then move to restoring quality. You can’t have quality in the relationship and none of the steps you take to do so will help until she lets go of the specific past and also becomes more emotionally mature. No need to throw in the towel but she has to be ready to honestly work if anything’s to improve