It's entirely about self confidence.
Every single woman I have ever fancied has believed they were a catch, or at least faked it well enough to hide their insecurities initially.
And it works for men too, I've had far more attention from women when I feel good about myself, regardless of how objectively attractive I am.
Right now I feel quite good about myself. Objectively I'm fat, I'm in my 40s, and look way worse than when I was a well toned, athletic 20 year old. But because I've got a new job recently that involves the office instead of working from home, I'm having to dress a bit better, be a bit more groomed, and I've lost a stone or so compared to 6 months ago. I've also had a pay bump, and I'm working in a role where I feel like I'm actually achieving something.
So while I know I'm nowhere near as hot as I was two decades ago, I'm looking better than I did six months ago, and that's given me a boost in confidence. Which has made me a bit more naturally outgoing, which means people are responding to me a bit more positively, which reenforces the confidence loop, and now suddenly I'm getting a lot more interest from women.
Which admittedly is annoying DP somewhat!