Because he felt so secure in his masculinity while still living as Suzy, Jacob (then a park ranger) was equally comfortable if Diane, as she puts its, "Barbie'd him up." Suzy was, after all, a stereotypically hot, blue-eyed blonde.
Diane posits that my experiments gussying up my girlfriend likely sped up Oliver's gender awakening because it was a chance to try on femininity and ultimately choose masculinity.
When it comes to the matter of just how "normal" it is for a woman to be critical of her own body, that's what Jacob's first few therapists thought, too. No one understood it, until Jacob did.
What matters is this: People are always changing
From the day we're born to the day we die, we're in flux. People are always discovering new things, absorbing new information, and adjusting their preferences. How we identify, and what we claim as being intrinsically "ours," changes. Significantly.
Had Olivia wanted to transition while we were still together, I would have supported it. My girlfriend was a gentle, nurturing person. And that wouldn't have been changed by a pronoun, body part, or new wardrobe.