Where the skin goes, is important.... To me, however, it is FAR more important where the HEART goes! At the moment you find that your current love's heart is entwined with someone else's... the only way I can describe the feeling is to have your sole sucked out of your body and it becomes hard to want to breath. As you said - the fact they just haven't "slept together"... really just becomes details!
I understand your point and feel for you!
I'm sure may others on here do too. We're with you!