It could be a bit of both. I personally don't masturbate for multiple reasons, one of the main ones being I enjoy feeling the sexual frustration build and build until I actually engage in partnered sex. But the problem with all the studies I've seen on male/female masturbation rates is that they rely on self-reporting. Women might low-ball their estimates because they don't want to be judged by researchers. They might also not qualify their masturbation as such because they don't always reach orgasm when they do it.
Said studies:
Wow I love that you stated that - Ive tried that a few times too letting the energy build up before I release with an actual partner. and that feels so good as well!
https://steemit.com/porn/@awakealiveaware/what-it-feels-like-having-a-porn-addiction-as-a-woman-pt-2 :) Heres my part 2 if you want to read