When a man frequently cheats on you?

I have found out that my partner of 13 years has physically cheated on me with several women.He claims not to have a valid reason for this apart from he's a man and thats what men do if they have the chance( without being found out)..as if thats not bad enough i also found out that he has been having on cam-cam even paying a subscription.My head is in emotional turmoil and my heart cut to pieces but, he minimises the problem saying that it's only fun and there's no contact...what to do? i really love him(never felt this way about anyone) but feels like he's really abusing that love and me...i know people will tell me to get shot of him, but although i'm not blind i love him and like to repair whats left of our relationship (it's been a long time) anyone else out there been through a similar situation and can offer advice? also he was abused by his mothers entrusted friend when a child,i'm sure this has some bearing on his current outlook on and love,trust etc but again he refuses to have help (if needed) for this as he believes it was an experience that helped him to grow up-and still has memories of the women who in her late sixties/ early seventies at the time was very beautiful? i feel sure this has influenced his outlook and impacts on our relationship .please help really struggling to cope .