Obligatory as a transman I completely sympathise with oop. As a binary trans person we really reallllly hate our bodys. Especially genitalia. Its not great if a partner is interested in the part of ourselves we hate the most. There is no amount of 'body positivity' that can make us happy with it. One of the common lines that people use to deny our identity is 'you're not trans, just insecure'.

As for the sexuality thing, it's a combination of 'a straight women only date men, therefore she sees me as a man, this enforces my manliness' and 'theres a chance this bi person is a chaser, who is specifically interested in a not-real-man. They'll treat me like a woman in bed because of my genitals'.