Also: I agree. It's pretty much always a tedium. Now, American series almost always suffer from that: not just the sex scenes are used as filler, and could be replaced with a line or two suggesting the events if relevant. House of Cards is my go to example: just take the British original for how you can condense the story by a factor of 10 without any loss. Putting it that way: it'd be hilarious if a compression format would work this way.
While we’re expressing opinions: in a show about navigating a partnership that accepts seduction as a necessary part of intelligence work (not solely of a romantic nature, but often), where the main characters are also being seduced by the capitalist lifestyle — I suspect some smart people might also view those less-clothed scenes as contributing (and even critical to) the underlying themes.
I'm with them, I don't enjoy those scenes (in general - haven't seen the one in question). Not because I'm a prude, I just find them a little boring and they usually take too long - and often are immersion breaking themselves with how they clothe or position characters to appeal to TV decency standards. An implication and a fade away is enough for me, unless something pivotal happens within the scene itself.
I agree that there are many stories where the fade away works just fine. I’m a bit baffled at the use of The Americans in this context though. It is distinctly not one of those stories, but one where each such scene — down to the literal blocking of action — helps explicate the narrative in terms of both plot and emotional arcs.
For me it's just boring filler and I skip them.