Mmm... Not quite? I guess it's more just a day to acknowledge couples and people you have a strong relationship with by giving them chocolates and gifts. Though in Japan, it's usually more expected of the women to give that stuff to guys, and then guys return the favour later on White Day, in March. Though I heard western countries don't have White Day, and both girls and guys just give each other stuff on the same day.

[It's simplifying it a bit, but... Honestly it's just a gift exchange.]