Your "theater volume" is very small, but with this being a basement and your theater open to the whole space, all the concrete, anything small is going to result in complete loss of any Tactile Response.
As I suggested earlier, if your total open room volume is less than 3000cu.ft. you may be OK switching to ULS15s... but I think you will be unhappy with the end result of those speedwoofers.
Frankly, I'd ask her, respectfully, to deal. I'm not trying to offer relationship advice or dig into your personal life, but unless you've got a huge mess elsewhere in the house and you don't contribute to the home and household... you've got the right to your own thing. If it means something to you, take a stand for it.
I had to put my foot down on my Lady griping about my rig after discussing it with her and trying to involve her. It just took my reminding her that she agreed to it and I didn't appreciate her snark. She got it. *shrugs
Anyway... to solve the situation, in the basement, you are going to be making a serious sacrifice downsizing as you are discussing. If it's not a big deal, that go for it and see what happens. If it's important to you, then take a stand. If it means bribing her with a new iPhone or computer, well...
But just so it doesn't get lost...
How much open space are the Subs exposed to?