ROM vs Ripley's Aquarium - which is better for people with mobility issues?

Just wanted to get some feedback from people who've been to the ROM recently or Ripley's Aquarium. My wife has some physical issues that make standing for long periods or walking long distances difficult. Now here's where things get tricky: she doesn't use assistive devices of any kind and will absolutely not use any of the venue-provided wheelchairs since a) she doesn't feel she's at the point where she needs one and b) she doesn't want to take one away from someone who really needs it.

She's a big fan of dinosaurs, so for sure she would want to see the dino exhibit at the ROM, although I doubt very much we would confine our visit solely to that area since neither of us have been to the ROM in decades. She's also a fan of marine life of all kinds and has never been to Ripley's so she'd definitely want to see as much as she could there.

Given these requirements and restrictions, which do you think would be the better choice? Which venue do you think has more available seating for someone who would need to sit every so often while touring?