I'm on my third person.
Fertility window for men is slightly more forgiving
But women don't behave as if that window is like a bathroom window, small enough to just get some air and put your hand out perhaps a dove might land on it or a squirrel does something nice but not scary
You don't find a relationship. You build it, and you build it as soon as humanly possible, with the absolute minimum amount of ego, arrogance, pride. Do it with the desperation of dying, since if you don't connect with this person, if you don't get to know each other for what you are and appreciate each other, and build, it's as if you're dying. Perhaps worse.