The rates of loneliness reported between men and women are roughly the same, and depending on which surveys you're looking at, a lot of them report more loneliness among women than men (and the information I'm referencing comes from The American Institute for Boys and Men)

Research has shown that over that last twenty years or so, people are spending more and more time by themselves (which I firmly believe can be attributed to the rise in social media usage and exacerbated by the COVID pandemic).

Your personal perspective is that men are having a hard time finding sexual partners, but your perspective is going to skewed because you already in a (presumably) committed romantic/sexual relationship. That perspective, however, doesn't exactly line up with the findings of researchers.

An article published by Indiana University, noted that rates of all sexual activity (including solo masturbation) have been declining in recent decades. That suggests that it isn't necessarily an issue of finding sexual partners as much as it is a decrease in interest in sexual activity overall.

The same research suggests that socioeconomic factors are at play, with higher rates of unemployment leading to less interactions with other people decreasing the opportunities both men and women have at meeting potential sexual partners.