Boyfriend won't admit to taking pictures of other women when we took a vacation together?

I confronted my 50 year old boyfriend after I found pictures of other women that he took pictures of in their swimsuits, up close shots of their body parts, when we took a vacation together. 17 pictures in all. He did this last year too on our first vacation together, but the pictures were very far away. This time he was bolder in taking close up shots. I told him it was perverted, creepy and that he needed help and that he should see a male therapist. I told him it felt like he had cheated on me. Those pictures made me sick to my stomach. I mean, wouldn't that be a normal reaction? He said that next time he will leave his camera home. He said that the women were "just in his way" when he was taking those pictures. (sigh) He says that he would "never" cheat on me. That I am the only woman for him, there is no other woman that he wants to be with. He wants to marry me and why can't we set a date for the wedding? He said he would never leave me or forsake me.