Later on, Ben was killed in a burglary, leaving May and Peter all by themselves, as she continued to raise him as her own son. Peter cared too much for her, so he forbade himself from revealing to her that he was the heroic Spider-Man, since he feared the shock of seeing her nephew as the very thing she despised (thanks to the Daily Bugle's smear campaign), might have been too much for her. Later on she became romantically involved with one of Spider-Man's most hated foes, Doctor Octopus, although their engagement fell through.
More on Marvel.com: http://marvel.com/universe/Parker,_May_(Aunt_May)#ixzz3E3gTKH18