I can see your point and I would feel absolutely pathetic if she started to sleep with her friend. However, several years ago before she meant me, she did live with him for about a year because she needed a place to start - nothing ever became of that. Things do change through. However, this is a loan and I know that my ex's heart is driven primarily to get our daughter into a safe school district and stable living environment. I know my ex will pay me back - I have no doubts about that.
I really want her to have her dreams come true - even if that means that she ultimately rejects me - as long as I know she is happy. So even if I knew that she will ultimately reject me at the end, that is not enough to stop me from trying my best to make her the best version of herself - to help her as much as I can to see her dreams come true. That said - there are boundaries and there is a line between being a caretaker and a caregiver.