I don't believe any human beings are, 'toxic.'
For me, I've recently discovered, I think, it's okay to love some one, even if they aren't good for you, you aren't good for them, or you weren't good for each other. Better to love them, than to hate them. You can love a food that isn't good for you, with out having to eat it...
Kind of a really simple thing; but, very hard to in practice to realize and recognize. We need to transform, some times, to move into a better relation with other people; but, I think, some times, we try to do that, with out realizing, the transformation can not occur while we are in their lives. It's as if, if we could change, it would work out; but, we can't change while we are with them, and when we do change, we won't be able to be with them, because it won't be right for either of us. And I think that makes us want to stay, because we don't want to lose the ones we love, so we cling to the ghost of what could never be...
There are rare cases, where people who get a divorce, get back together. Why is that rare, I wonder? ...I think it's wonderful, though, when two people can recognize their own faults individually, change, adapt, recover, and grow back in to each other...
I dunno..