I agree with you in part, Roses.
I think it's too early to tell whether they have a strong marriage. They clearly love each other, but the strength of a marriage is so much more than that. They are only now being tested.
Day to day, they are probably as happy as pigs in muck, they're on permanent holiday with their baby and can spend all day playing. If they want to dabble in a bit of work all they have to do is ring up one of their charities, put in a quick video call, get their PR to tip off the media, job done for the day. What they think of as work really isn't work as the rest of us know it. Not that either of them are lazy, but much of what they do seems to fall squarely into the category of what dear Len Goodman would term "faffin' abaht"
The strain will be around what their future holds. None of their "projects" have any longevity. They need huge amounts of money to sustain the lifestyle they clearly aspire to.
As Royals, they didn't need to generate a living, they earned their keep by doing unpaid good works. I had huge hopes for them as Commonwealth ambassadors, I really thought this was going to be their role. I'm so disappointed that they stuffed up this opportunity, but I think they have.