Good for you on all counts, Ms. Emilybee.
The conventional wisdom seems to be that male sex drive (probably measured by frequency of ejaculations) is maximum at about 18, then gradually decreases as men get older. Female sex drive, by contrast, is maximum when women are in their thirties, and can remain high for many years after that. This is apparently correlated with testosterone production increasing in women as they age beyond 30, while in men testosterone production gradually decreases as they get older.
If so, this seems consistent with your feelings, having reached 30, that you need more sex beyond the already-high levels of sex you've described yourself successfully experiencing for the past 15 years.
This also adds emphasis to the desirability of married women who are about 30 and older seeking extramarital sex with lovers who are significantly younger. For example: quite a while ago a member of this forum (whose screen name I can't recall) commented that his wife, who was in her fifties, took only men in their twenties as lovers.