Some tests to tell if someone is being unfaithful are walking behind the partner while he is on the phone and asking how he spent an evening out to see if he answers with details. Another test to check for a partner's unfaithfulness is to schedule a lunch with the partner or surprise him to measure his reaction to an unexpected event.
Because cheating often involves a smartphone, if a partner pulls away quickly from a significant other before she can see his phone, that is a sign that he is unfaithful. For this test, a person that sees her significant other on the phone can walk up behind him to give him a kiss. If he reacts by shielding his phone, it is a warning sign.
Alternatively, another test to check a partner's faithfulness is asking about things that happen when the partner claims that he is working late or spending a night out with friends. If he answers questions about the evening with a great deal of detail, it is a sign that the partner is faithful. However, if he gives short answers and tries to avoid further questioning, it might be a sign of infidelity.
In addition, when a partner schedules a lunch on short notice, she can check if her partner responds enthusiastically or if he rushes through lunch as quickly as possible. In addition, if the partner leaves during the lunch to make a phone call, that is a warning sign of unfaithfulness. Also, a cheating partner might claim that he is too busy to stop for the surprise lunch. If the partner seems hurried or tries to rush through the surprise lunch, it could be a sign that he is unfaithful.