You live alone?
No. I think some couples are just more private than others.
I don't think there are any couples who prefer the bedroom to smell like the toilet.
If you flush the toilet at precisely the moment after you take a shit, the vacuum force of the toilet venting down the waste line will pretty much keep that from happening. That's basically prison rules.
Where is this magical prison where nobody farts?
They flush the toilet every time they fart, of course.