I am reading a book on fear of intimacy, which is why I am bringing up this topic. I believe my wife has this issue, I have it to some degree, and it sounds like both of your wives could be candidates too. “Carrying the weight of the world” is an exercise of fantasy. It is a defense meant to protect themselves from some underlying fear. It gives them a sense of control, since they can have a hand in directing the fear and uncertainty of the future, it makes them feel important and authoritative since they are the serious one taking one these huge responsibilities, and it makes them a martyr, vying for the affection and compassion of others for the sacrifice they are making.
All this is an act of self delusion to protect themselves from feelings of vulnerability, abandonment, whatever. Look into their FOO. While many like to ridicule my emphasis on FOO, situations like yours seem warrant looking into their past to help them. Behavioral changes for this situation are only band aids and will never work for long.
The fact of the matter is that both your wives have stayed with you for many years, in spite of their self imposed unhappiness. If leaving would have made them happier, I think they would have left. So they have a need to stay with you, even if they cannot see it. And they won’t be able to see it until they can break down their walls, which they don’t even know exist. To me, this is all FOO related. If you haven’t seen a counselor addressing this stuff, you might think about it, rather than assume there is no hope left for the marriage. If could be that your wives are just very, very dysfunctional and in need of a whole lot of help, a lot more than can be provided on these boards. Just my take.