From Sonos:

”If you place the Sub horizontally on the floor, don’t put anything on top of it. Leave at least 1" clearance along the top of the Sub if placing under furniture.”

I'd say it will still sound great. I'd just be concerned if any accidental movement of the couch would damage the unit or tug hard on the power cable, but you could loop that around a leg or frame to stop that from happening.

That sub can sit anywhere you have a plug socket and still add something extra to your setup. There must be somewhere you could hide it. Mine is behind the couch where I sit where I can almost feel it as well as hear it!

The Sonos sub is pretty understated as subs go. Should be easy to find a compromise with your better half.

There are brackets available to even mount the Sub on a wall.

It’s always a good idea to add new hardware when your partner’s not about

You might look at some extenders to raise the couch a bit.

When discussing speaker placement with a spouse it is often best to pick the most obnoxious possible spot for the initial placement. From there you can compromise on where you really wanted them.

Another reason why it probably won’t work is because the sofa will be a very uncomfortable place to sit on when the sub is driving bass through it:-).

Thanks for the tips everyone. And for the funny spouse advice!