In my opinion, lifetime silver is pretty useless - no good perks and only a small increase in points earned. Gold is easy to come by with credit cards/other status matches, and is not particularly great, only useful perk is additional points on stays, so you likely won't be in silver status much anyway. Lifetime status at gold or platinum is a loooooong way off for either of you, so I think the year by year opportunity to get status is probably more important at this point.
In my book Marriott Platinum is the only status that really gives you anything - ok chance of upgrade when you ask nicely, lounge access (if there is one), some kind of breakfast at most (not all) Marriott brands, plus when you hit Platinum you get 5 suite night upgrades (which are not guaranteed, and some people complain that they never actually get an upgrade using them, but can work well if you travel slightly off season - both the requests I've used have gotten me upgrades to junior suites).
In your situation, I would concentrate all your Marriott stays with the person most likely to get to 50 nights in any given year. If that is you, I'd book all of your travel and DH's work travel using your account (if his work travel arrangements will allow this). If the reservation is in your name, you will need to call the hotel and tell them that your husband will be arriving before you, so you want to be sure his name is also on the reservation. That way would be able to aggregate all of the elite nights under your account. Not 100% foolproof - you are supposed to get credit only for nights when you are actually in the room, but we've done this many times without an issue (my DH doesn't even have a Marriott account).
I know upgrades etc. are not super important to you, so I wouldn't get too excited about killing yourself to get to 50 nights, but if you happen to have a heavy travel year, you might find a use for the platinum benefits.
ETA - I'm having a very love/hate moment with Bonvoy. I've got a good few years of Platinum from when I traveled more for work, so lifetime Platinum would only take me another couple of years, if I maintain status and get a bunch more Marriott stays. On the other hand, 50 nights a year means pretty much all my hotel nights need to be at Marriotts, so I'm feeling like a Bonvoy hostage at the moment and kinda cranky about it.