i have no idea why he refers to those 80-120 flings as relationships, but I think I agree with his general sentiment.
Personal experience: currently 24, got a first gf at 20. Things faded, i felt like I needed to get out and explore while in my 20s, plus I realized that I wasn't that much into her + we had to move to different states, and long distance sucked.
We broke up almost a year ago, zero regrets about that, it was the right move. Was mopey af for a while, but i eventually got over it. Slept with a bunch of women since then (mid double digits), from lawyers to college students to engineers to hairdressers, varying degrees of hotness and wildly different personalities, but none of that made me happy for longer than a couple of hours at a time. I was kinda ecstatic at first, since I didn't realize I was actually a person who can do that well, and it was a great confidence boost, but it was just a temporary feeling that faded quicker than cocaine high does. In fact, I walked away from that experience even emptier than what I started with. The only things that hold me together right now are an amazing group of friends I accidentally stumbled upon ~2 years ago, my job (which I like), and the fact that I am very competitive and can't afford to lose this game.
Still feeling empty af, but not even because of the ex. Watching days floating by, lacking any purpose, and successfully pretending that everything is fine and dandy, because I feel that's the right thing to do if objectively you are doing fine. It gets easier, OP.
tldr: relationships or flings won't fix anything long-term for you.You gotta do your thing and find your happiness on your own. Whether you end up finding it or not, it doesn't really matter, because you will be busy enough with your journey and develop coping mechanisms.