TV size is perception. Your perception of the TV size shrinks over time.
It will for your SO too, just as it did for my wife. We started with 55 inch HD, to a 65 inch HD, to a 75 inch HD and now have a 75 inch FALD Sony 4K.
With each step up she thought it was "too big" at first.
She's on board with the next upgrade being an 83 inch or larger.
We sit about 3.5m away from the screen. 11-12 feet. Our room is about 4m wide
This is all about your field of view. Much like theaters ideally fill 40-50% of your field of view, a TV for mixed usage should fill 30% of your field of view, and if you primarily watch 4K movies and shows, 40-50%% is ideal.
30% of your field of view is the minimum you should have.
Good explanations here:
Our TV Sizes to Distance Calculator helps you choose the right size TV for your space. The optimal viewing distance is about 1.6 times the diagonal length of the television. For example, for a 55” TV, the best distance is 7 feet.
www.rtings.com
Maybe sit down with your SO and look at this together?