I actually agree with all the points you're making but you're never going to get people to agree with you or get anything changed with inane incel wording you use. I think her willingness to have threesomes/foursomes comes completely out of left field and contradictory to everything in her romance. She won't sleep with you act 3 seemingly because you need to build trust with her but suddenly she's willing to do group sex? It makes zero sense whatsoever. The guy who wrote Shadowheart also wrote Halsin so it leads me to believe he's just a self-insert for him and that's why she's so willing to do. And because of the fact that Halsin reads as a self-insert I don't consider anything involving the two of them to be part of Shadowheart's character. It's just weird shit this guy put in the game for himself which is a shame writer's shouldn't do that.
Ah the internets favorite insult strikes again. Despite my 'incel' writing as you have dubbed it the reality will not change, will it? Cuck, zoophile, degenerate are all words with meaning and words that simply apply to the situation at hand. Sure I could've used a more flowery language but the description I gave was more than enough for you and others to agree with.
I don't see why I should be more diplomatic in my wording when dealing with people who would ruin characters with a disgusting fetish that is zoophilia. (It is a form of degeneracy and no tip-toeing around it will change that) As for the dreaded cuck word? Is it not cucking for a partner (in this case companion) to sleep and lust after another while in a established relationship? (Even more malicious is to write all of that after that characters story was already finished/established)
In all honesty I won't hold my breath when it comes to these changes being made, despite the writers talent that he has show throughout Shadowhearts story he is still catering to certain type of audience. Would it be nice? Sure, but at the end of the day it is only a game.
Don't take this response as me being snappy because I don't mean it that way. Maybe my wording isn't the best suited for changing minds or garnering support but if you think you are able to convey the situation any better and what you would like to see changed feel to free to do so otherwise the cuck romance will stay as it is.