Did I do something that bad to deserve this? Our daughter too?!
think this thru....what on earth could an 8 month old infant have done to "deserve" this??????? your mind is grasping at straws to avoid looking at the cold hard truth........this man is not interested in being a partner or a parent. he has nothing to offer, contributes nothing, and takes his leave whenever it suits him.
and honey, you can't change any of that. YES he's using. i posed this before, even if you take drugs out of the equation, is his behavior in ANY way acceptable?
let his sister "keep" him. she seems to know it all. well good for her.
you need to take every precaution to keep yourself, your finances, your belongings and your daughter safe.