"I Want You To Date..."

Why?

The man who I fell in-love with, who found someone else and is still with her, who wants this separation, wants me to date during this time.  Is it so he can feel better about himself, like we're equal in the fact that although married, during our separation we've met others we want to "test out"?

I can't explain how much that sentence has been hurting and bothering me. 
How can I meet someone, better yet, seek out someone when the person I've imagined my whole life with, the person who I gave up my name for, who I gave my heart to, is the person who has hurt me the most and is someone I still pray to God to allow him to realize I'm the one for him.

What is wrong with me?  Why am I the one begging him back? 

I don't know if I can imagine what it would be if we did call it quits. I don't know where we are now but I know he does still love me.  But that one day, if we did call it quits, and stopped the daily conversations, the occasional meetups - and I see him at a store, with or without someone.  How can I look at him and merely think, "There was the guy that I once loved.  There was a guy who I pictured growing old with."  How can I imagine those thoughts to be so weightless when they mean everything to me right now?

I feel empty, I'm sleeping in later, I don't like being enthusiastic or chipper, I don't want to make anyone feel better when they are having a bad day.

I honestly don't know what I'm doing with my life.

Day 51 since he wanted a separation.
I feel like I'm regressing.