Are you sexually and romantically involved with both of them, or just him?
Why not have other relationships besides the couple? If you found someone who wasn't part of a couple, then you could be free to be publicly affectionate with that person and perhaps the secrecy you have to maintain with them won't hurt so much.
The world opens up... when you do.
"Oh, oh, can't you see? Love is the drug for me." ~Bryan Ferry
"Love and the self are one . . ." ~Leo Buscaglia "