Necrophiliac

Necrophilia (n.): the urge to crack open a cold one.

A person, such as Cutaway or Jimmy Savile, who is sexually attracted to or has sex with dead bodies...

Technically, even if your ex was totally 'dead' in bed, you are not a necrophiliac ... she has to have shuffled off this mortal coil and gone to join the choir invisible before you can claim to have porked a stiffy.