<human>: Unfortunately I've fallen for a friend of mine, lets call her "Sally".
The only unfortunate thing about this is that Sally is and has been in a LTR for 3+years. 

I met Sally last year in a class we both took. We were more classmates than friends though. We ended up having a class this semester and have grown closer since. Sally knows I find her attractive and I believe she is attracted to me as well. I've kept my distance and so has she, but the distance we keep is obvious and awkward its become hassle to deal with. 

The semester is coming to an end and I will likely never see her again- aside from holiday "Happy so-and-so" texts. I want to tell her how I truly feel about her- as I feel it will help me move on and get over her. I realize that in doing this I am effectively ending our pseudo friendship which has no room to grow (due to feelings of mutual attraction and the possibility of her feeling as though she is betraying her boyfriend). 

Is this a good idea? If not, why?

Can you give me a shortened version of the text?
<bot>: Is it okay to confess my feelings to "Sally" and effectively end our pseudo friendship? I will most likely never see "Sally" again, whether I tell her or not.