I like my bestfriends boyfriend..what do I do?

My bestfriend, lets call her Jen, started dating this guy, lets call him Ale. I started liking Ale a month or two ago and my feelings keep getiing deeper. they have been dating for three months. they are always holding hands, making out, cuddling. i just want to cry whem i see them together like that. I know i may sound lame or like i am jealous. but hey, obviously i am jealous. my bff is with an amazing guy that i like a lot, how could i not be jealous of her? thanks everyong. no rude,stupid,mean comments please.