This makes me feel all mixed up: jealous, yet happy that T has someone to love. Do you think I can tell T about these clues, or is it too creepy?

Huh. I don't know. I'm trying to think how I'd feel in her shoes. A few months ago someone (a gay man) asked me if I was queer (I am) and provided all the "clues" that had led him to that conclusion (including the fact that I was wearing colourful stripy socks that my son had chosen for me that this guy interpreted as being "rainbow socks!"). It didn't bother me but I think I'd have felt more at ease if he'd just asked point blank without telling me his reasoning.

Maybe just ask your T if she's a lesbian (or in a relationship with another woman--some people feel uncomfortable with various labels). She might not tell you or might ask why you ask. But I think it's totally okay for you to ask. She's doesn't have to answer if she doesn't want to.

FWIW my t and I talk all the time about what it's like for me that she's straight and whether I feel that this interferes with her understanding me or makes me feel awkward around her.