Well you may be a bad person, though I doubt it there are so few people in this world whom I would say qualify for that dubious distinction. The statements of your actions and thoughts here clearly don't put you among the few sorted brutes I personally would classify as such. An abusive parent is not a fit guardian for any child it will only result in perpetuating a further cycle of addiction and abuse when these children arrive at adolescence and adulthood. Nor is it fair to them to be with someone physically unable to raise them or fair to you to be burdened with the labor some task of raising four small children. I hope all works out for all involved.