Perhaps. a bisexual wife or gf might have an additional acceptance in terms of knowing what it is like to be somewhat different.... But I would think, that a woman who is attracted to other WOMEN, would want the REAL thing, not a man dressed as a woman. I do see how it can be easier for bi sexual women in some ways, but still, I do not think it makes them more able to be attracted to us. I don't think they would seek us out due to their bi sexuality. Not being bi sexual I cannot really say, but it would just seem to me that a person who is bi would want either a man or a woman who is that and not a mixture. I could be wrong, so I guess we would need to hear from those who are that could validate or not validate the theory.
As for my wife, she is not in any way attracted to other women. Her acceptance of me is due to how I make her feel loved and cared for, period. She tries not to think much of my being transgendered, as there is nothing she can do that alters or changes it. She accepts it that it is me. She is not one who likes it, or understands it. Tolerate could be a word I suppose. From our conversations, she is looking at it as dealing with something that she does not care for, which we all have things about our partners that we do not care for, so that we can reap the rewards that having that partner give us.