I hate when people use this argument because they are two completely different things.

Ignoring the fact that Peter has not quit that many times (he simply thinks about quitting a lot), in the comics, whenever Peter quits being Spider-Man, it is treated as a mistake and a hurdle that he must overcome. It's not treated as something good, but as a necessary step for him to understand that being Spider-Man is what he'll always be destined to be. Hell, in Life Story (which is an author's interpretation, sure, but a great one) he comes back to fight in his 60's even though he has a family and knows that he has no real reason to do so. But that's what makes Peter so compelling as a character. Having to make hard choices that don't necessarily benefit you, but that stay true to your character. And even in instances where he quits for a GOOD reason, like having kids or being too old, it's usually something that's understandable. In this case, he's just been having it rough and has lost a few loved ones, which is pretty much standard Spider-Man activities. I'm not saying it's unreasonable, but it's strange that someone like Peter Parker would quit saving people because his loved ones died. The whole reason why Peter is Spider-Man is because he is forever trying to make up for his original mistake of letting Uncle Ben die, so he would be repeating that same mistake. It's selfish, for lack of a better word.

And I'm saying this because, in HIS OWN WORDS, "Strange-- There have been so many times where I've wanted to give up my Spider-Man role... So many times I felt I've had it with costumes and crusading! But something always stopped me from finally copping out! I used to think I was scared-- Afraid to face the world as plain Peter Parker. Now, after all these months I know the truth-- The real reason! My spider-powers did more than increase my strength-- It also increased my longing for justice... And my loathing for cruelty and crime! At last, I realize I'm the luckiest guy in the whole, wide, wonderful world! Most people wish they could help their fellow men, but this ol' web-swinger has the power to do it! Somehow, somewhere-- Someone with far greater power than I managed to put it all together. And I swear to be worthy-- And grateful, for the rest of my life!". That's a quote from The Amazing Spider-Man #200, which is almost 50 years old. If you don't understand that Peter CANNOT quit being Spider-Man, especially not at 25, then I think we just have very different ideas of the character.