Bisexual person here, maybe I can help

A longing for **** sex doesn't make a man gay or bi. A lot of cis straight guys have it with their girlfriends.
Many of them don't talk about it because they fear that other men will see them as less masculin (except kinksters, but that's a different talk) but it's really not that uncommon.
HOW you want to ***** is not really about beeing straight or gay or other. WHO you want to **** is what unites us as a community and shapes our experiences.
Or in other words: Cis gay guys having sex with trans gay guys doesn't invalidate anybodys sexuality. It's still gay guys having sex, even if it might not be a 2 penis party.
However.
if you feel like bi or bi-curious fits you more, than you would be welcomed in every bi comunity.
In the end you are the only person who knows and can define your sexuality and I'd encourage everybody to experiment with labels and see how they feel. Just be respectful and educate yourself while you do it (great start btw!)
Good luck on your journey