That reminds me, another age difference that was handled with tact was Numair and Daine from Tamora Pierce's Tortall universe. When Daine was eighteen, he was thirty or so, and had been her magic teacher.

They both acknowledged that it could potentially be problematic, but they were equals by that point, able to consent with trust and enthusiasm, and those who mattered wouldn't judge them. I think it was implied that Numair knew how it looked and wouldn't've said a word about his feelings if the situation had been different.

Also, they gave each other permission to leave the relationship with no hard feelings if they found someone closer to their age whom they connected with better. (That didn't happen, though; everything worked out pretty well.)

= Multi-Facets.