No, there's no evidence that he was gay, bisexual or that he raped his wife. The idea that he was a "libertine", as Retha Warnicke calls all of the men involved in Anne's downfall, comes from his execution speech which you can read in my article at https://www.theanneboleynfiles.com/george-boleyn-lord-rochford-part-3/3772/ or at https://www.theanneboleynfiles.com/rip-george-boleyn-lord-rochford/5481/ where he talks of being a wretched sinner and having sinned shamefully. George Cavendish, a contemporary, theorised that George was referring to promiscuity with women but historian Retha Warnicke suggests that George was speaking about homosexual activity. However, there is just no evidence to back this up.
In my opinion, I think George was just following the usual execution 'choreography', i.e. confessing that he was a sinner and deserved to die. He was of a Reformist persuasion and used this chance to 'preach' at the crowd and also repent for the life he led. We cannot read too much into the last words of this man.
What does George being gay and that the Boleyn were “a highly dysfunctional family” have to do with one another?