Pisces men tend to be passive in love and are vulnerable to pressure. If pursued by a proactive woman, he might agree to go on a date even if he doesn't really like her. It's also important to be cautious if he works in a female-dominated workplace.
Pisces men rarely take the initiative to invite women other than their girlfriend, so the possibility of infidelity increases depending on the environment. If there are daily contacts with women and situations where she is not watching, be careful. It would be wise to have a detailed understanding of the women he interacts with closely.