Your questions indicate you are not detached or don't fully understand the concept of detaching. Detaching is for YOU and the betterment of your present and future. It is a long and hard process, I wont lie about that, but it will help you become more stable as an individual (I am not suggesting you are unstable but a divorce brings out instability in many, many ways). It will help you see that even if your marriage does not work out you will be okay.
So really, who cares if your H notices you are changing and getting a life? It shouldn't matter because it's all for you and your children. It's for you and their well being, not to impress or try and "win" back your H.
When you are fully detached what he says or does or doesn't say or doesn't do will have little bearing on you. Of course there will be days of sadness and hurt. As I said, we are human beings and not robots. But how you deal with that hurt is the key to healing. Don't ignore it.. feel it and work through it. I highly suggest seeing a counselor for YOU.
Make moves and plans and improvements for you. Begin to rebuild your life as if your H is NOT coming back and the only R the two of you will have is that of co-parents.
Be vague about what you do if he asks. Offer no information and don't ask about what he is doing. Add some mystery to yourself. You have the power to change the dynamic so you can get to a better place.
If I can do it so can you. At one point last year my H told my he could see all kinds of changes in me but they just weren't good enough for him. Okay. That's fine. I didn't improve my life to be "good enough" for him. I improved my life so I could *have* a good life for me. When he said that to me I simply said in a very good tone "thanks for sharing your thoughts and have a great day!". Again, not the reaction he was expecting but at that point I had stopped allowing him to control me.
I made new friends, I restructured my business (I am self employed) and I volunteered with lots of projects in my community. I took a yoga and pole dancing class. ALL FOR ME!
Did he notice? Who cares! I noticed and felt better and that was and continues to be my goal. He filled his days/nights with an affair and constant partying. I chose to add substance to my life along with counseling and a goal to be the best woman I could be. I still have lots of work to do but I am on that path.