I have a protagonist who has to deal with the guilt of failure. He works a lot, usually away from home, and has little time to be with his wife/girlfriend. He always creates for himself the duty of protecting the ones he loves. But one day, she is killed while he was away from her. He wasn't there when she needed him. He failed his duty.
If he was a teenager or an average Joe, maybe this would be a little more comprehensible. However, the problem is that he is not. Instead, he is a late 20s, tall, muscular, handsome, charming, cool, successful, powerful, smart and skillful medieval [fantasy] warrior.
That's a lot of qualities, I know (that's another problem I still need to fix in him; and yes, he has flaws and some life problems), originally the intention was that he was the aspirational type of protagonist, the type of protagonist the reader would like to be, but I think I went the wrong way and he became closer to a Marty Stu than an aspirational character, and then now he's just a character with his personal story. But anyway, the real problem here is that his qualities put an astronomical weight on his failures, because he has so many qualities, that failure is not expected, and if it does happen, it's just disappointing, shameful and off-putting.
This failure is discussed/lampshaded in the story (although it's not the main theme), the protagonist knows how bad it is and feels guilty about it, and his enemies/haters mock him about it. But I think it's not enough to convince the reader to accept this failure and to take this fact seriously.
What can I do to prevent this negative effect?