The reality is that love goes beyond sexual identity, well for me anyway. I loved my late wife deeply and had a daughter with her that we bought up (well until my wife died when my daughter was 16). Walking with my wife as she shared her death with me was something that is the closest anyone on this earth could come to "sacred".
Yet now I love David the same way, the only difference is that he's a man. We love each other every bit as much as my wife and I loved each other, and that doesn't negate or take away anything from my past love. Both are true love. Both are real.
This a talk from two transgender people who married after only 6 months of meeting. They're further along than I'd ever be on sexual fluidity, but they very much have some wonderful things to say about it all.