My older 2 were the same age when we first went, and my husband is a software engineer who is a total introvert

Obviously, I'm the extrovert of the 2 of us! Anyhoo, those are GREAT ages. February will be lower crowds too, I'm hoping so that helps with the hubs.
Things that we try to do every time that help keep everyone sane and might work for you -
1. Into the parks early (I think they open at 9-10am so it's not super early) and back to the hotel to have rest time at lunch
2. Never stand in line for meet and greets, we do a character meal. Totally worth it.
3. Disney Junior at DCA was wonderful for downtime in the afternoons - it's dark and cool and not overstimulating. The Tomorrowland pavilion (I don't know what it's called, Land of Tomorrow or something?) worked well for this in DL. The Goofy's House play area in Toontown was also a big hit.
We try to just go with the flow with the kids and retreat before they got to the point of no tomorrow. Good luck, it will be awesome!!