Upside, good to hear from you, and very glad that your xh is coming out of this. I have come to the view, having been at this a looong time [changed my name here because I suspected that my xh had sussed out who I was] that there are different types of MLC, as well as different responses.
If we start from the assumption that no-one is perfect, we can still look at 'normality'. Basically there seem to be crises where the lbs comes to realise that they had a co-dependent marriage, and that the marriage was problematic. Doesn't mean the WAS isn't having a MLC, but the underlying marriage was problematic. Then there are others where the LBS is basically OK - not perfect, but OK, and the WAS is the one with problems. This isn't any predictor of who comes out of it, but I think it does explain a variety of responses to MLC that we see here.
We all have to work on ourselves: I am a much stronger more involved human being for having gone through this. I still love my xh, or the man he was, although I am detached from him, and living a good life. But in his case I can see it is a severe mental illness which he did not recognise, and has tried to treat himself, with disastrous results. Sounds patronising? I don't mean to, but all the signs are that he is also realising that things are seriously askew with him.
So I would say, all the advice is good, don't put your life on hold, work on yourself, and see it as a great opportunity to do things you always wanted. But ultimately I agree we should trust our gut.