How important is it to have human failures and scandals in an epic work of fantasy fiction?

Tolkien only had like one failed hero out of the entire Fellowship of nine heroes.

My supposedly "Good aligned" characters should all have moral flaws.

I was thinking of having the title character cheat on his girlfriend with his superior officer (Her idea). The thing is, unbeknownst to Brandon, his girlfriend, Malia, is a telepath and will know right away what has happened. So Brandon, a First Lieutenant, will bang his Captain, Rio Aso, just because she was asking for it! I'm not exactly sure when and how to write this up, but it's a goal!

then Malia, who is supposed to be a Healer, could struggle with her inner demons about unforgiveness towards both Brandon and Rio Aso. What if Malia is later needed to heal Rio Aso, but doesn't want to do so, because she stole her man?

I decided Rio Aso should be like this slightly older Playette, who decided she wanted Brandon in the sack from the first time she met him. What do you think about this?

How important is it to have human failures and scandals in an epic work of fantasy fiction?
Post Opinion