>>Try sleeping on your side, even though doing so won’t solve the root problem.

There's an 'old-time' method for keeping a bed-mate from snoring : sew something approximately the size of a tennis ball to the center-back of the snoring person's pajama top.

Speaking as someone with bruxism (jaw clenching), resolving to not do something before going to bed doesn't change what I do when I'm asleep, so I wear a mouthguard. I'd expect that simply resolving to not sleep on your back would have the same issue.

If you're trying to not sleep on your back, that tennis ball might help, as would a mattress with for-side-sleeper firmness.

As a side-sleeper with wide shoulders I can tell you that anything topped with visco (slow rebound) foam (e.g. Tempur-Pedic) will help. If you already have a firm mattress, try a 3" topper of 5lb visco foam. I did that with one of the beds at our lake place and if anything it's better than a Tempur.

Just my $0.02