It will come, you cant force it (believe me I tried lol!) - remember this is a process, just go with the emotions you feel and trust that you'll end up where you are supposed to be.
You don't have to accept that its over forever, you dont have to accept that you'll end up divorced, the only thing you need to accept is that RIGHT NOW you & your H are separated and you need to live your life according to that - none of us know what tomorrow will bring so we can only deal with right now.
You're right. I really have to focus on right now, this minute, instead of, say, how I'm going to introduce another man to my daughter someday. Oh, and where in the world I'm going to meet him. I get way ahead of myself really quickly.
