Oh, c'mon man... Don't you get into whitewashing mode in case of Louise behavior. She's not innocent, loyal or true. Can't say no to any instance of group sex and conveniently gets into every threesome roster.
I bet in some extended
ORS: Special Edition, we would get deleted scene with Louise and Lena would high-five during Jeremy and Ian threesomes and make some jokes on being eskimo sisters afterwards.
It's a miracle Stan was able to save his innocence in that damned house, because any other man visiting Louise and Lena is in danger of being reversely gangbanged. You would think they live in house for rent, but in reality Lena's flat is a horny jail.
I hope these nasty girls at least leave poor cat out of this debauchery!
I doubt Jeremy has ever considered Louise as a keeper or proper wife material. Their relationship is made purely because of mutual convenience. Nobody really can judge other part, as he is, as you said it, a wannabe player and she is wannabe groupie, getting down on any male who is considered in demand by her popular peer.