From the astrological point of view, romantically, the most favorable relationships for Cancers are either with a Scorpio or a Pisces or with a Taurus or a Virgo. On a business or professional level, there is great compatibility with a Capricorn, as they can complement each other in many ways.
According to Astrology.About.com, in a romantic relationship between two Cancers, there can be a deep connection and understanding, due to the similar needs and goals. However, it can become frustrating when monotony settles in. The partners should attempt to see relationship issues objectively and avoid emotional scenes.
Astrology-Online.com states that there is an especially deep connection between a Cancer and a Pisces, whether in love, friendship or business. The emotional resonance and mutual compassion and empathy makes this relationship very satisfying for both partners. They also have the similar needs and preferences when it comes to intimacy and home atmosphere.