Your being a doctor brings a lot into perspective for me ... maybe. My BIL is a doctor too ... highly intelligent and motivated guy (he had the top marks in our country of origin the year he graduated) .... I like him a lot. His W, however, gets driven crazy by his hours at work, his lack of understanding with her life (she is an artsy person, and at present a SAHM), and they have different ideas about childrearing too. Doesn't help that they're from two very different countries, and were brought up totally opposite. My dear BIL is totally clueless with emotional stuff (mmm, much like my H), but you seem to be getting it.
Look, without even realising it, my BIL can come across as a complete know-it-all (and he does know most of it), and maybe a little arrogant. You have to know him really well, and have seen him severely sloshed a few times, to understand him, and not take anything he says or how he comes across as personal. Please understand that I'm not saying this is you, but I have noticed some of these traits among the doctors that I do know, and I often wonder how their wives deal with that.
So, my advice here is try not to overthink things. Let your W see some of the emotion behind what you are feeling, without being overly needy, and whiny. For instance, if she asks you if she should stop training with her personal trainer, say "I would love for you stop training with him, but I will not impose that restriction on you." Look her directly in the eyes when you say this, and let her see some of your pain. You are doing great coming home earlier, and giving her some space, so don't change that. On the other hand, don't allow yourself to be a doormat either.
All you can do is try different things, allow yourself to be human (and we all are here, making our usual humanly mistakes), continue with what works, drop what doesn't, and listen (really, really listen) to what your W says, and validate her feelings (whether you agree with them or not). Oh, and hell no, she shouldn't be discussing her feelings about the OM with you, IMHO. That's like making it real for her ... and who knows where that will lead. Of course, the feelings could all be one-sided (her side), and the PT has no clue. Which doesn't mean you don't work at DB'ing.
Also, take time out for yourself too. Can't be doctoring all day, then coming home to taking care of the kids, and then just going to sleep. You'll go nuts. You need some down time too = GAL.
Take care.
PS If BIL ever reads this, then let me say "sorry, bro' ... love ya regardless"
Me:57 H:52 M:28 Got another lawyer last year and filed. D35,S/D twins28,D22 EA4/04 End? Who knows? "Life is like a mirror. Smile at it and it smiles back at you." — Peace Pilgrim