How do you stop yourself loving someone you cant have?

i cant stop the heartache its physically hurting me i cant stop crying and its kinda not good for my kids.(no he isne the kids dad that im broken over)im not a kid either i didnt fall in love until the age of 27 and now a couple months later its gone he and me were perfect why did i fall for this guy out of everyone in the world and i cant be with him its flippin hardcrap this is any ideas on how to cope and please no crap off poeple