Now to answer you question more directly, I believe you should discuss your fears with him so he understands exactly where you want your relationship to go for both of you, otherwise you might grow resentful of him and he may have no clue as to why.
My boyfriend is currently in his third year of medical school.
Public displays of affection PDA show a lack of self-control. It is not the norm.
I decided to do the mormon thing and just not think about it too much right now. If you decide to stay.