Its very tricky thing to manage in a relationship. In this modern era, its impossible to restrict friendship of the opposite sex.

Other than a lot of trust, the ideal thing is to have some agreed ground rules with our partner.

One rule that we practice is transparency. Inform the partner. Who, where, time. And the partner can say no, I dont like u to meet that person.

We also agree that we can suprise checks each other phones. This is something that we actually do.

Its not foolproof vs cheating, but better than nothing.