Simon didn't realize he was cursed. The Japanese manual basically said he had broken his back in the battle and that he got worse and worse until he felt he was at death's door. In response to this, he went to the family graveyard, and it was there that a mysterious woman told him about the curse and then vanished as if mist.
Wonder who this woman was, if a ghost residing in his families graveyard, maybe it was an ancestor, such as Sypha? Wouldn't that be weird if Captain N got it right? (there's an episode where he goes to the graveyard to fret about Trevor's tarnished reputation and a male Sypha appeared to him).
At any rate, Simon couldn't learn the truth until he went to the place that could tell him the truth, which he didn't do until he thought it was all over.
Here's the translation:
http://www.vgmuseum.com/mrp/cv2/documents/CV2J.txtJudgment appears to have retconned the "broken back" thing, and just went with the wounds getting worse. Here's Judgment's ending:
Thus the rift in time was mended, and all were returned to their respective
eras.
Six years later, a mysterious woman would tell Simon Belmont of the curse
placed upon him.
To free himself from that curse, he would have to collect Dracula's remains --
his nail, heart, rib bone, eyeball, and ring -- and burn them all at the ruins
of Castlevania.
And with that, Simon set off on a new quest...