Others have covered that there were internal supports, so they were supporting nothing at all. But let’s assume they weren’t.
I’m going for an intentional underestimate - so let’s say there are 10 people in your layer (I think 8 is more likely), then 24 above them, 18 above them, 18 above them, 25 above them, 14 above them, and 2 above them. I think most people would agree those are underestimates for each ring.
That’s 101 people being supported by 10 people. If we take another underestimate that each of those people weighs 100 pounds (45.36 kg) then that’s 10,100 pounds (4581.28 kg) - or 1010 pounds (458.13 kg) supported by each of the 10 people in your ring, completely ignoring the weight of the metal rings visible in the picture. So I think it’s safe to say it was mostly the internal supports at work.
Adding on to the reasons others posted: Put yourself in his shoes for a moment. If you take off a year for him, that puts an immense amount of pressure on him. Pressure to go to the same school as you, pressure to go to school at all, even pressure to stay in the relationship.
It’s always gonna be “They made this gigantic life decision to their detriment for me, so if I change my mind about anything and want to do things differently, like by going to a different school, or not going to a school, or wanting to break up, then I’m a huge ungrateful jerk.”
Putting that kind of pressure on someone isn’t really cool, especially if they’re actively discouraging you from doing so.