Welcome to SR. You will find a lot of experience, strength and hope here.
It would be a good idea to read some of the "Stickys" posted at the top of the forum page. There is a lot of time-tested wisdom there that can help you get through this tough time.
As for you, have you considered going to Al-Anon? I know it can be tough when you have little ones at home, but some meetings offer babysitting. Don't knock it until you try it for a few times - I was originally wary of it but it came to be my lifeline.
It is hard to say what you can expect when your BF gets out of rehab. I'm sure someone else will come along here on this post to give you some better ideas.