personally i would not break the trust.
the main thing is now you know how he feels. that was the point. its no point in using it against him. and breaking your trust with teh person.
that information to use against him is going to serve no purpose.
instead its time now to really have a heart to heart talk with him about where your relationship is going.
i am also not the kind of person who tells someone whom to have a friendship with. but it certainly would hurt my feelings that he was telling someone else how he felt about me - instead of directly telling me.
this is the professor - univ. chair guy right?
'romance' is such a different idea to a univ guy. i have lots of family who are v. high level professors and i swear some of them are v. asexual. so i can see them describing what he wrote as 'acceptable as romance'.
but it doesnt really matter what he feels. he may feel you are like a sister (for all you know that might be high praise in his books) and that he is happy with the way teh relationship is - BUT what about you?
what do you want?
i would sit down and talk to him and bring up how he feels about you and what he wants. its a place to see if he lies or tells the truth. ask him if he feels you are his lover, best friend.... and see what he says. and then see if that is what you want.
you guys just moved in together didnt you? i remember you talking about that. was it november or july.
if this is not what you want see if you can work out with yourself if you can live together till you can move again.
personally i want more than this. i do not want to be anyones sister when i want to be their mate, their lover.
but i will say i dont see the emailing as unfaithfulness. because seh is a 19 year old girl? i know i have and i know others have 'intimate' (not sexual) and deep friendships with people other than their spouses. but trust ur gut in this. if it feels like unfaithfulness then treat it so.
in a way i am so happy for you that this has come out and it is really making you sit up and see what YOU want out of life.
i am glad this acquaintance had the gall to come and tell you this.
mama you will get thru this too.