"Art is the only sensible person in this love triangle" is a surprisingly common interpretation! T. H. White goes for it and so does Mary Stewart. Guinevere and Lancelot (a.k.a. Bedivere) may angst but Arthur is like "Whatever."

Except in Rosemary Sutcliff's Sword at Sunset where he absolutely loses his shit, but Artos is Very Troubled in that adaptation anyway.