What would Arthur do?

I've done another blog post on people and Merlin's magic but this is the biggest one out of the whole show. Merlin is Arthur's dearest friend but he has a gift which Arthur hates. Will Arthur feel betrayed or guilty? Betrayed because he trusted Merlin and now he's found out that he practises magic. Guilty because he's executed his kind, killed his lover all the while Merlin was protecting him and Camelot from harm and Merlin never got any credit for it. Personally I think Arthur will feel guilty but what do you think?