I am kind in the same way that you are, mcgrew. There was a woman I was kind to, and she started taking advantage of that kindness. Of course, I was a dumb 20-something kid and let this happen a few too many times, and I was also a dumb man and slept with her a few times. There was never talk of a relationship, and she dated a few men without a word spoken about it by me. I really did not care, nor did I really care much for her (I saw us as friends with occasional benefits when our desires aligned).
Much like Billie, the woman that I had been kind to apparently thought we were in a relationship, despite the fact that we hadn't spoken beyond normal pleasantries in months, and hadn't slept with each other in over a year. I found a new woman, and the new woman and I started dating. The woman I had been kind to became hysterical after she found out, screaming at me about how we were supposed to be together, that I was the nicest to her and had to love her because of that, and that she couldn't believe I would cheat on her.
Leech woman has been out of the picture and new woman is my girlfriend of almost a year now. The reason that I add this comment is that I did something that mcgrew didn't do, and that was I slept with the woman I was kind to because I gave in to my urges. As a warning to the future, don't do that. It just makes things messy.