I meant in the sense that (theoretically) she'd be married to a man for appearances only, while actively in a relationship with a woman. Said man of course being OK with this (again, theoretically) for his own reasons. Think something along the lines Cumberbatch & Knightley 'The Imitation Game'. But yes, "sham" may be too strong a word for what that would really be.
Someone who's bi can choose to be monogamous in their marriage. It's about as hard to imagine as it is to imagine married heterosexuals who don't cheat on their spouses.
You appear to have totally missed the point.
My initial comment was based on the premise that Carter was 1) in love with Angie (who is not a man) and 2) married to a man (who is not Angie.)
While certainly not the only possible scenario by any means, I merely posited that this *could* touch on the necessity for bi and gay people in the 40's & 50's to enter into marriage with a member of the opposite sex, mostly for appearances sake. Often while still in a relationship with a member of the opposite sex. Sometimes even with the consent and support of their spouse.
That's all. I'm not saying Peggy couldn't possibly love Angie *and* later enter into a genuine marriage with a man, just suggestion that the above scenario might be one interesting facet on which they might touch *if* they went down that path.