Cancer and Capricorn are opposite signs, and almost all of us are attracted to or have a fling with our opposite at some time during our lives. It may not work forever, but often soul mates aren't meant to be forever, they just come together to teach each other something important, and we never forget them. So the Cancer person is gentle, sensitive and loving, but so is the Capricorn one, they just don't show it as much. The Capricorn is more practical and less dramatic than a Cancer person, also less changeable.
Your Gemini Moon represents your emotions, so Gemini is also a changeable sign, though one where your emotions are ruled more by your head than your heart. You are lively and fun.
The Capricorn comes off as more serious, but is sensitive and more reserved. The Scorpio Moon makes her sensual and psychic, and also is a serious influence on her. But her emotions are fixed, and she is loyal and trustworthy. I think she is in it for the long haul or wouldn't bother at all. I think you are a good balance for each other.