hello, i just wanted to say if you feel it is karmic, you are probably right. Go with that feeling, and see if you can trace to something more elaborate...say, your relationship with that person. If you still feel it was as a lover, then go with that, too. I've experienced similar things, but also have gleaned that re-enacting anything physical is merely a means to working something out. Meaning, you could probably work it out without getting physical, but physicality is such a quick way to do it! If you are both practitioners or experienced in meditation, you could sit and work it out together in silence. Talk about it afterward, do it in small sessions, whatever works for you both.
Hope that helps!