Should I trust him, should I stay with him?

I have been dating this guy for about 5 months. he lives in a different state and we travel to see each other on the weekends, we see each other almost every weekend. He told me about two or three months into the relationship that he takes girls numbers at the bar and asks them to send naked pictures of themselves to him (even when he has a girlfriend) I kind of blew it off... but he has since showed me a picture of a bartender who sent him pictures. It physically made me sick to know he was personaly taking numbers and requesting pictures. We broke up brifly that night and he said he didnt want to lose me and that he would no longer do it. Since then he has received more pictures which he had requested... he obviously lied to me becasue he said he would no longer request the pictures. He says the pictures are humorous.... I do not beleive he will sleep with these women but i just dont like the idea. I do not mind him looking at pornographic pictures such as movies, playboy etc. but i do not like the "personal relationship" of exchanging phone numbers