I posted this reply in the other place you left your comment, but am moving it so it's here with the comments from others.
It's quite common for our newly out spouses to temporize in this way. They want to retain the comfort and security of the known, and often still want our support and care (and our financial contribution), as well as the freedom to explore their newly declared sexual orientation.
In my opinion, it's extremely selfish, and supremely dismissive of our feelings that the blow their announcement has raised in us. We can't simply turn the dial from "spouse" to "roommate," and it's unreasonable to expect it. That they can do this, and so easily, is itself another blow. It's also disingenuous to suggest "co-parenting" while living together is somehow "best" for the children; to see parents become roommates is disorienting, not a more healthy choice than actual separation, which has the benefit of clarity and preparation for the future.
I would ask you to shift your attention from him and what he wants, and why he wants it, and think about how you feel, what you want and need. I would also suggest that you find yourself a confidante in your life--a friend or relative--you can talk to, and a counselor/therapist just for you, to help you sort out your feelings. Also, visit a lawyer, so that you can have a clear picture of the options open to you--legal separation, a temporary order for child support, etc. Knowing your options can help you make a decision about what is best for you.