It's good to have friends outside of a relationship. Honestly, as much as I would love my partner, I wouldn't want to be stuck with him 24/7

. Giving each other some space to be by ourselves or with others cultivates personal growth. So, I think it is fine that a single woman/male is close to a married/partnered woman/male. If there is trust, respect, and communication within the relationship, then a situation like this would not matter. Now, if a problem does arise, then the woman/man would have to think about whether being in the relationship/getting married was the right thing to do. If the man/woman cannot even trust his/her partner, why did he/she get married in the first place, right? Sure, humans are prone to jealousy or fear losing the partner to another person. But to an extreme level, the man/woman can jeopardize the relationship especially if there is no evidence that something is amiss. Now, if the man/woman fears losing his/her partner to another person, then he/she would have to ask himself/herself what would the reason be for this happening: relationship has been sour do to whatever (i.e. inattentiveness, too many demands, control issues, previous dishonesty, rumors, finance, dull sex or lack there of, loss of initial passion, no spontaneity, stress, etc.), married a player even though instincts told him/her not to at the get-go and thinking that the player could be changed, and/or past experiences of bad relationships.