No its not good while talking to other guys if you are in a relationship. It is normal to have friends of both sex and still have a boyfriendgirlfriend why would it not.
And girls should know her self that she couldnt have to talk with another guy.
Talking to other guys while in a relationship. Because another guys can flirt and make force to you. Talking to other guys is normal as long as you are not flirting or doing anything out of the norm of friends.