Being kind and gentle won't do a thing, you know. Be firm, or she WILL jump from affair to affair, because after all nothing happens if she does except gentle rebukes.
Forget everything except the one fundamental human truth: people respond to incentives. You must make it more unpleasant for her to be IN the affair than out of it. And since any break-up with someone you're in love with is pretty darn painful, you need to make it quite unpleasant.
