Generally, it's a little bit of jealousy and curiosity...but you have to remember it's the old, "I don't want my spouse any longer, but yet, I don't want you to have them either" in some cases. If your h comes to your home, don't be surprised if he goes around looking to see if there is evidence of om. It's almost like marking their territory. LOL!
Why are they asking about if you are dating, etc.? Because if you are, you are alleviating some of their guilt because they are doing it. They are so relieved because they can then tell themselves that if my spouse is doing it, why should I feel guilty about doing it as well. Surely, if you are dating, then he can too and you cant' say anything about what he's doing either.
You are far better off not telling them what you are doing. Keep some mystery about your situation. It doesn't hurt for them to wonder.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.