OP-
You need to slow down. I get that you are feeling liberated by your decision, and that's okay. Hold on to that positive energy, beacuse you are going to need it - there is a lot of work to be done, and likely some challenging times ahead.
Telling your husband and children is just not something you can plan and expect to go any particular way. You can remove yourself from the situation, but the process of divorce can be slow and it's often difficult. You have been working this out for yourself for some time now, but it is not realistic to expect your children not to need at least as much time to work it out for themselves. You'll need to tread carefully for their sakes, and they may not be able to move as quickly as you into a new life. The reality of single parenting is that your childen's needs will drive your life from now on, since there is no one else to lighten that load. As excited as you are, remember when you first became a parent: you could not have accurately predicted how you would find parenting, no matter how much you read, heard or thought you knew. Well, the process of becoming a single parent is like doing that all again.
Based on your first post, it also looks like you are making assumptions about what you are going to be able to do that may not hold up. You do not get to decide who leaves the financial burden of the house, regardless of who leaves the actual physical building. The two of you, if mediating, or the courts will decide on the disposition of the marital home. If it being foreclosed upon, that will likely effect both of your credit reports.
Additionally, you cannot base your new life's budget on child support from a man who has a history of not working. Your lawyer can work up estimates on the child support formulas all you want - you cannot get blood from a turnip. If there is no paycheck to garnish, you're not going to see any money. Having a court order does not make him into a suddenly responsible person who is going to work enough to see that the obligation is taken care of.
Your life and the life of your DDs is going to drastically change. Some of the changes will be good, but some will be hard. Really hard. It doesn't mean it isn't the right thing to do, but you have to go into this with your eyes wide open.
I'm not trying to rain on your parade but I really do think you're getting ahead of yourself by looking at apartments before you've told your spouse. You are not single, divorced or even separated yet. You have made the first decision.
Congratulations.
I wish you a successful journey on your new road.
have you both already discussed this as a possibility...or is he going to be floored? 
