I am sorry that you are going through a separation period, right now.

Will you both, be in individual counseling, through this separation. How long ago, was the post-partum depression?

How long, is the limit on separation, before deciding where to go from there? How does, this friendship of his, factor into this separation, if it does at all?

What is the goal, of the separation? Is there a reason(did I miss a previous post, or just am forgetting the story line--please forgive me, if I did and it's not sticking out in my mind, at this very moment), that led to this decision?

Mainly, my advice, would be therapy for both, he step back from this friendship, until your marital troubles are resolved. There be a time frame, say a few months, to come back and review, instead of being an indefinite arrangement, that could delay results.