For me, manning up has involved GALing (getting a life) and stopping being in shadow of W, taking control and responsibility for myself without being disrespectful of her...in fact I hope she senses that my respect if anything has increased considerably.
Detaching and giving space is very very difficult and with your W pregnant this is going to be doubly hard- I would say offer her help but impress on her that if she doesn't want it she has a responsibility to say so - you are not a mind - reader.
Now is also a good time to get thinking about a few 180s - these are useful as they force you to put your focus on you rather than on your W and you're right - do not invest energy in trying to change things which you cannot.
Personally,I have found exercise /physical things suit my GettingAL. This would fit in pretty well with some of your goals - but the key to these activities is to find ones which you can maintain because they are for you - not W.
In addition to other reads you are no doubt working your way through I would recommend Manhood by Steve? Biddulph.
Best - GFI
Me: 40ish W: 40ish Together: 20 ish years Married: 10ish Years