A girl who is frequently neglected by her boyfriend becuase of any given extracurricular activity of his.
Rock Widow: Girl whose boyfriend never spends time with her becuase he is with his band
Frat Widow: Girl whose boyfriend is always at his frat house
Weed Widow: Girl whose BF spends 90% of his life smoking weed
Track Widow: Girl whose BF trains for track constantly
Pre-Med Widow: Girl whose BF is premed and therefore always studying
Cock Widow: Girl whose BF is secretly gay and gettin' cock
Susie: Bryan can't go to prom with me. He's gonna be in Baja for a surf competition.
Betsie: Hah, Surf Widow! Sucks for you.
Adrianne: Hey, where is my goddamn boyfriend?
Christie: I'm sorry to tell you, but I believe you've become a Coke Widow. He's doing lines in the bathroom.
Simply insert the offending activity into "-widow".