I recommend standing up for multiple relationships. Try to change social standards. Put your energy into that. It’s a way of sublimating your troublesome feelings and trying to make society safer for people who are lovers. You don’t actually have to do anything that would hurt anyone else.
Think about why you want them. A lot of times, there’s an underlying need that isn’t really about the person at all. There’s usually more to lust than just physical attraction. What makes them mentally or emotionally interesting? Why aren’t you fulfilled in those areas, and what can you do about it?
I’ll throw my lot in with @wundayatta. If you find you can’t practice what you preach, start preaching what you practice. But the truth of the matter is, if you love to a ripe old age, it cures itself. So live to a ripe old age.