the MCs contract states he has to breed 30 *human* women, so the number by the heart displays how many human (non-supernatural) women he's marked. Candy, Brenda, Sunny, Angie, Dolly, Sab, Brandy equals 7 - you're correct that Susy hasn't been marked yet, she will when the Linnet's get their story update.
Glad you enjoyed the game!