Yeah, but he can't have him. That's the whole point. Arvo and Torulf are friends with benefits, without the friends part. That's literally the very blatant summary of the problem - Arvo has an emotional attachment to someone who feels absolutely nothing but lust for him. Torulf drops meetings with Lake for Arvo just as easily as he sidesteps Arvo to go fuck Lake.
Why would you want Arvo to stay any longer in this abusive relationship?
As someone else put it, my headcannon Torulf route is the Lake route, where everyone are happy and Torulf is blueballed. xD