It can be difficult to tell if a potential partner is likely to be unfaithful. It's important to pay attention to warning signs such as if they seem overly secretive, or if they have a pattern of dishonesty or cheating in past relationships. It may help to consider whether they are comfortable discussing the topic of fidelity and trust openly with you. If they avoid talking about these topics or show an unwillingness to commit, this could be an indicator that they may not be trustworthy.