I fully accept my SO and I have from the onset. I am not bisexual.
I think the degree of acceptance is proportional to many factors: when the wife/girlfriend finds out (while in the throes of new love, or after 20 years of marriage), whether it is a first or second relationship, whether there are young children at home, how connected is the couple to begin with, whether the wife/girlfriend has conservative religious views, where they live (urban vs. rural, and some cities/counties are more progressive than others), how much the wife/girlfriend has traveled (she has met a wide variety of people), and I'm sure other things that don't come to mind at the moment.
I also want to say that I know two bisexual women. Each one has been in long term monogamous relationships with men and women, not just a dalliance or two with same-sex while in college. One of them was in a lesbian relationship with another woman for 10 years and she is now married to a man. The other is single at the moment, but has been in 1-2 year relationships with one or the other. Anyway, they both told me the same thing: although they embrace the idea that everyone should present in a manner that feels good to them, they are not personally attracted to people who gender-bend. Being bisexual does not guarantee an attraction to feminine males or masculine women. Oh, and a third bisexual GG that I know fell in love online with a newly transitioned, MtF TS. This TS moved here and they were married. They divorced two years later. The GG is now in a relationship with another GG.