The sex at the beginning of the relationship must have been epic for a man to not only put up with this but to actually marry her too. I have no other explanation why a level headed man would subject himself to that type of torture for any other reason than that.
In a lot/most/all? relationships, you get more and more comfortable about being completely "yourself" with the person very gradually (or maybe I'm just a really guarded person). It just so happens that her true self is... a tad insane. It likely took her several years to decide she could be her utterly nutso self around him and believe he would still accept her. It's very unlikely that she ever acted that way around him before they were married.
There's a couple who comes into the place I work who are both in their late 60s/early 70s and the woman verbally abuses him right in front of me all the time and I feel really embarrassed for him. I don't understand that relationship at all but they're still together and probably have been for 50 years.