Is dating my old college lecturer wrong?
It’s not wrong. Now that the course is over, you are free to become involved, unless you’re going on for a PhD in this department. If you are, then some ethical issues do arise, and of course you cannot ask him for letters of recommendation. If anyone tried formally to accuse him of dating you secretly while the course was in progress, that person would have to provide some proof, and of course there wouldn’t be any. Though colleges and universities try, for good reason, to prevent involvements between students and faculty, there is a view that this is highly unrealistic. Telling two mature adults that they can’t experience an attraction to one another while one is teaching and another is taking a course is not just unrealistic, it’s an impossible demand. You and your tutor have handled things about as well as you could have, with the possible exception of the public kiss in the bar. In the circumstances, given the presence of other students who might make assumptions, that was unwise.