Are you suspicious that your husband is cheating on you with your hot mother-in-law? You might want to think about the signs that your partner is being unfaithful. If your mother-in-law has been mentioning your daughter's ex girlfriends and making you jealous, she may be jealous of your relationship. The signs that your husband is cheating include: Talking about your daughter's ex-girlfriends and pretending to be his friend..