A rather perverse nobleman comes to Paris - one who despite his unpleasantness, is of political value to Louis and so is indugled.
Musketeers alone hold no more than a passing interest for him, but when he realises an actual Comte is among their number, it's a different story.
Louis convinces himself Athos will be fine (and as a servant of the Crown he should be prepared to put France first) but Treville realises otherwise and comes to the rescue (though Athos was in the middle of rescuing himself).
Up to author if ends up Treville/Athos.
TL;DR Louis 'rents' an unsuspecting Athos out to an important person at court, but Treville steps in.
Comte!Athos/OMC, Protective!Treville, hurt/comfort, betrayed!Athos
Musketeers alone hold no more than a passing interest for him, but when he realises an actual Comte is among their number, it's a different story.
Louis convinces himself Athos will be fine (and as a servant of the Crown he should be prepared to put France first) but Treville realises otherwise and comes to the rescue (though Athos was in the middle of rescuing himself).
Up to author if ends up Treville/Athos.
TL;DR Louis 'rents' an unsuspecting Athos out to an important person at court, but Treville steps in.