Absolutely; sounds like he is engaged only to keep his fiance happy but really is looking for the single life perhaps to cheat? He need to be honest with his fiance. He cannot have it both ways.
Dump the lil slu*s @$$. You deserve better. She never really loved you to be doing something like that behind your back. You deserve someone who loves you and only wants you NOT everyone on the block. I mean that is just the one you saw so who knows.