So long as you know and are able to avoid getting involved its fine but if you are looking for lurrrve then you will get hurt when he/she doesn't change
So....if one identified one´s partner as a "player" then if one wanted a meaningful relationship, then one should "back out"
But this isn´t borne out by real life, as if you indulge in the section of R&D one seen innumerable examples of women getting involved with identified "players" and yet do not want to leave them........despite opinions and advice by "esteemed" ABers.
There is also a suggestion that some women are "drawn" to losers.
get a good looking best mate to help out when you and b/f are out one night by her trying to get his attention on see if he takes her on,while you "nip" to the ladies
how about just assume he's not until he does something to suggest otherwise! It's hard work dealing with 'trust issues' caused by new fancy's exes! Paranoia will destroy ya!