Oh girl, you totally belong here!

Now my questions for you are:
Why do you think you've waited this long to consider dating? Was your marriage so awful that it scarred you for 20 years? Is your natural introvert just so happy alone that you didn't want to risk the intrusion? Is sex just not that important to you? (Not a judgment, people are all across the spectrum, but for many people, a desire to resume a sex life would have propelled them into the dating pool sooner than 20 years.)

Is it a desire to be with a man that is driving you, or just a concern that you won't have anyone to care for you in your old age? It's a legitimate concern, that last, but one that a man may or may not fill. Unless you date someone younger, odds are that you will end up caring for him. Even if he IS younger - my boyfriend is 4 years younger but has stage 4 lung cancer. I expect any care I need when I'm elderly will come from my kids or friends, not from a guy, unless I date someone much younger.

I do get the bit about missing male energy in your life. Like I said before, that doesn't HAVE to take the form of a long-term monogamous relationship unless that's what you're looking for. It's also possible to have a long term monogamous relationship that doesn't involve living together.

My best friend was married to someone similar to herself, both introverted artists. She loved the way they could be in different rooms, doing their work, for hours at a time and not feel crowded by the other, or go off for months at a time touring and then come back together. I think, in addition to the grief of his death several years ago, she also is hesitant to date because she is afraid someone new might demand too much of her time and attention.

Sounds like you did the work to heal from your marriage a long time ago, so I guess what I'm getting at is, what do you REALLY think is the reason you've waited so long? And what do you really want out of a romantic partner at this point in your life?