Sounds like this is about you, not your partner. Also sounds like he's right.
No matter who you're with, or for how long, other people are likely to find your partner attractive, and may harmlessly flirt. It's human nature, it happens. Your partner (and you) are also likely to find other people attractive, nand may be flirty yourselves. Also, human.
But if you and yours have an agreement to be monogamous, and you both are, there's nothing to be jealous of. A relationship is not a monopoly on someone's interest or attention, rather, it's an agreement for two people to be together exclusively in a given way.
(And do yourself a favor: stop comparing yourself to other women and vice-versa, as if all women were in some sort of competition or beauty contast. It's nonproductive and just plain destructive when it comes to decent relationships with other women.)