Love is about cultivating impossible illusions.
We transfer and imprint a lot of shit onto our selected mate they could never live up to, even if they were aware about how out of step our estimation of their resources are...
We never saw them break up.
It's an interesting question if they even got together again after warlord?
Because it would be pretty hard on her that first, he didn't notice she'd been taken over, and second that he just accepted that their love could die, which is ridiculous when you consider how she tricked Kathy into murdering Tuvix so that she could get her hedgehog loving.
She loved him so much as to kill his first born.
That's a rough sort of love I wouldn't want to fuck with or get inbetween.
She killed Tuvix!
Maybe Neelix was bloody happy to be rid of her, he remembers being murdered by the intensity of her love because he, when he was Tuvix loved her "wrong".
He's not a spider.
Death doesn't give him an orgasm.