Can I refuse the sexual advances of a trans friend?
What does the trans friend do that make you feel so against sexual advances?
His behavior makes me feel like we would become life partners but I don't feel comfortable with him
It may be a good idea to let your friend know how you feel. If you are not into them sexually then that is fine. There is no need for them to continue to pressure you if you are not into it.
I'm aware of all this but I don't care. I want to keep my relationship with him platonic.
You have the right to accept the sexual advances you want and reject those you do not want.