Help!

Ok, this morning I told him I wanted to separate. He asked why and I told him because I felt he needed time and space to think about things. Then he looked really uncertain and sad that I wanted to separate. I think I caught him off guard. He is still sad but it seems like he doesn't want to give up. He asked if we could have a talk about it tonight. So.....wish me luck!!
In our talk I don't want to come across too needy or desperate...any advice?? ahhhhhh

sigh....

M: 8 yrs T:14
Twins:7 S:5
BD:'NLILWY': Feb/2013
Mar/Apr/May: MC
June: "living in limbo"
Sept 12: H moves out
Oct 20: reconciling
Jan-Feb 2014:MC
Feb 2014: separating, and H moved out.