Anyone seen Into the Abyss?
Not exactly a serial killer (triple homicide) but still fucked up. The dude slaughtered 3 innocent people to steal a car, then got in a shootout with police when he was caught. He's spending life in prison, but some chick who I think was a lawyer assisting with his appeal (could be wrong on that) "falls in love" with him and marries him even though all they can ever do is hold hands under supervision basically. Then she gets pregnant supposedly with his child, and they hint that someone helped smuggle a sample out so she could get pregnant or something.
She isn't bad looking, seems pretty intelligent.... but she chooses to waste her life devoted to a scumbag murderer. You hear about this shit all the time with women being attracted to serial killers and such. I know some girls like "bad boys" but I would think a line would be drawn somewhere.