I loved the bit in the novel in which MJ reveals how unnerving (ulcer-making, really) it would be to be married to (or otherwise tightly involved with) a superhero that you really cared for.  She'd seen on the news where the enemy had been throwing cars at Peter.

That's the thing, in the Marvel Universe everybody's seen various superpeople in crazy fights, it's part of everyday life like car crashes or scandals or H1N1.  But when MJ watches the news, she doesn't see 'supervillain throwing cars at Spidey', she sees 'supervillain throwing cars at Peter'.  Quite a different thing, and a deep level of personal helplessness, sort of like being married to a cop or a soldier only worse, and and with live video of the dangerous parts usually at hand.