Impossible situation

There's always been attraction between me and my friend's boyfriend. We slept together a few years ago but nothing ever came of it. We have continued talking as we're all in the same friendship group and over time we have developed deep feelings for each other. I love my partner, he is wonderful but I can't stop thinking about the other guy. I don't want to hurt anyone and neither does he but we seem unable to stop what is happening. I feel like I am in love with 2 men. my partner is my best friend but we never really clicked sexually. The other guy knows exactly how to push my buttons. Any advice?