It doesn't sound like her penis is your only problem with her. It sounds like you're also frustrated with her self esteem and lack of long term goals. While these issues appear interconnected, most people want to be with a partner that has long term goals and cares enough about themselves to take care of their basic needs. If you are concerned that if you make her penis your reason for breaking up, I would suggest changing focus. You need someone who loves themselves, you need someone who takes care of themselves and you need someone that wants to work towards a future. While it seems you do care for her she can't give you what you need right now. You know more about the situation than I do so leave it up to your own discretion as to whether or not you want to leave things open for discussion IF she were to change. I think if your concerned making the breakup about her transness would be triggering then don't make it about her transness there are very clearly other issues in your relationship that are grounds for breaking up. Would you date a natal woman who has to be reminded to take care of herself, has no goals or ambitions, and no self-esteem? I wouldn't.