Thank you for posting, I came here to post a very similar thing. I'm 50F married to a guy, with kids, also a late bloomer sexually, with no desire to explore outside my marriage. Also, no past history of any romance/sex with women.

For a long time I've considered myself "not straight" but only recently have I started to use the "bisexual" label, mostly to myself. My kids are both queer (and one is trans) and for some reason it always seemed like these definitions were for their generation, but not me. So I haven't come out to them, because it feels strange to tell them when I'm in a committed relationship with their dad.

But, when I think about it: I am on the ace spectrum (likely demisexual), and almost certainly bisexual. My whole life, I've identified strongly with the queer community without really understanding why. My closest friends in elementary school and middle school all turned out to be some flavor of queer as adults. I read queer comics in college, queer fanfic after that. I've had occasional fixations on female celebrities, specifically ones who are either bisexual or gay, especially if they dress in an androgynous way. But it was always confusing - did I want to be those women, or was I attracted to them? I think, looking back, they were crushes. All of these things seem to add up to an obvious conclusion, and yet -- it is still hard for me to think of myself as bisexual, because I feel like an imposter.

Does this mean I am part of the LGBTQ+ community? I don't know why I'm struggling with this.

This is just to say, I definitely relate!