DB'ing is definitely a way to work on yourself. We all lose ourselves along the way, to our jobs, marriages, kids, etc. So, even if our M's are strong, it's always a good thing to revisit our passions, take stock of our personal goals, and so forth.
One thing that DB'ing helped me with .... immensely .... when I was going through the MLC drama with my H, was learning to detach. I find that helps me with all kinds of R's now. I used to get angry when I was hurt or upset, but now I just detach myself from whatever issue and am able to look at it more objectively. So, read up on the lovingly detaching section in the DB'ing book.
I know that when we are hit with the bomb, the tendency is to obsess about what is happening, how to fix it, how to protect the children, becoming depressed and despondent, and so many other spiralling thoughts (all normal, of course). Just know, that eventually (at least, in my case), you do get sick of your own nagging thoughts, and start to find other things to think about and get busy doing. Just give yourself time to process.
Anyway, your W is certainly going through something. Probably, feels like her youth is fading with the impending 40th birthday. Give her some space to figure herself out. You can't really control her, only yourself, so just be polite, but distant, keep certain boundaries, and keep making goals that lead to GAL. Also, avoid starting R talks, and if she brings it up, just try and validate her feelings (not necessarily agree with her, but try and understand how she may be feeling), and really try and listen. Leave whatever you need to say for when you are both in the C's office.
As for the birthday gift ... I would leave the grand gesture of an expensive plane ticket to Switzerland for another time ... it may seem too much like you're trying to buy back her affection, or pursuing in some way. I think it probably best to just give her a fairly generic card (maybe, something humorous), with a gift card to her favourite clothing store ($100 should be enough to not be too impressing) or a gift certificate to a day spa (we women love that no matter who gives it to us)? Make sure the kids remember her birthday, of course.
Take care.
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