@tedsmith512,
Yes, you are trying to justify this to yourself. ehBeth is correct. You are paying her and in exchange she is spreading her legs for you. The two of you may not view your relationship as prostitution, but it seems to me it is the same. Of course, you could find out for sure. Stop helping her financially. If she keeps spreading them for you, then it isn't about the money. If she cuts you off, then it was about the money.
Quote: I know everything she does, she tells me everything
You want to bet on that?
I'm sure you are. At least until she gets out of school and gets a real job. Until then, you are her meal ticket. It always pays to be friendly with your meal ticket.
It is only a matter of time before your wife will find out. Why don't you end this thing and stick to one relationship at a time. In this case, the one with your wife. Seeing as how you love her so much as you wrote originally.