I wasn't going to comment, but essentially.
Frank's former wife was supposedly like 20 years his junior. That's an extremely unbalanced power dynamic, and a very scary thing to be in, I'm sure.
The kind of guy who will knock around his terrified, cowering wife is not the same guy who will swing on a shaved Sasquatch in a frumpy black dress. John Flynt had a history of explosive and troubling behavior long before Frank married him, and age appears to have done little to dull that edge.
To be completely honest, my two cents on Frank are pretty straightforward:
Frank is an aging, short, fairly unattractive Asian man with a string of abuse allegations behind him and a dwindling fortune. A silver fox he fucking ain't. His options aren't exactly unlimited at this point in time.
He indulges Brianna to the best of his abilities, and she dotes on him (in her way), because both are aware of the blinding reality that they are all that is left for each other.
There's no busty gamer chick in Frank's future, and he fucking knows it. Even Bri knows on some level that the likelihood of ever finding another sugar daddy who will indulge her every whim is nonexistent. Neither of them is terribly desirable in any sense, and they're getting old.
To put it simply?
Bri isn't abusing Frank and Frank isn't abusing Bri. Neither party is getting fucked over here. They are together because they're two shitheads who have found the absolute only other person on earth willing to tolerate them, and so they've settled for the only option left.
This isn't love. This is a classic case of "I'm rich, you're breathing, neither of us is getting younger or hotter, so fuck it".