How to tell if your Cancer partner has a lover?

Fidelity fireproof

It is difficult to suspect the natives of Cancer; however, their imagination and romanticism can make them unstable.
Overall, they discard adventures, but do not forget that these children of the moon are more subject than anyone to fluctuating moods.
If they ever have an extramarital affair, this will be passing and they -probably- will regret it later.
To find out if your Cancer partner has a lover, look at him straight in the eye and ask bluntly; Cancer are incapable of lying.

Does your partner have a lover?