The TV show writers did a lot of emotional manipulation of the viewers. I saw the first few episodes of the first season, read "The Three Musketeers," and then picked up with the show again. I saw the Musketeers as anti-heroes in the book. Porthos had an affair with a married woman, and demanded money from her, as another commenter said. Her disabled husband was aware of this, but unable to do anything.

I haven't had the heart to rewatch the third season of the show -- too many deaths of sympathetic characters, too much destruction as a whole. I don't remember offhand anything about Porthos apologizing to Aramis for being abusive towards him. I noticed that Porthos showed a pattern of gaslighting other characters through the whole series.

I saw the shortened American versions of the episodes first. When I got the DVDs, I noticed that in the first episode, Porthos says about d'Artagnan, "Lively little bugger, isn't he?" I was disillusioned then that the show had made him the homophobe of the group.

Perhaps partly because I'm not a writer, the way the "heroes" treated each other was not something I really took personally. I feel your pain about a feeling of betrayal when a character you like/liked does something awful. *hugs*

The women on the TV show had a bit of agency here and there. I expected toxic masculinity from an action-adventure show focused on men, though. I'm glad you were able to express how you felt. I think I'm more desensitized than I should be to toxic behavior because of how ubiquitous it is.

I think of you and wish you well. Take care.