Many years ago, I met a guy who became my dear friend. Remarkably, we had almost the exact same personality. It was as if I knew him from the moment we met. We were fast friends. Over time, I got to know his wife and kids.
Then my friend was diagnosed with a rare and usually fatal disease. He fought hard for years but eventually, he died. It was tragic and earth shattering, particularly for his family. I made a promise to myself that I'd do whatever I could to help his family in the years ahead.
Several years passed and I maintained a distant friendship with his widow, speaking with her from time to time. One day, she came to me asking for my help with her work; naturally I agreed. Over the course of several months, we fell deeply in love with one another. One of those really intense loves where it consumes your whole world. Thing is, not only was this my friend's widow, she had also remarried.
She left her second husband right away, and we had a close, meaningful relationship for about 6 months. I could tell some of her attraction to me was that my personality was familiar to her, given that her late husband's personality was so similar to my own, or mine to his. That always gave me a strange feeling. She and I ultimately called it off, though with no animosity. The experience was surreal and yet honest and positive for us both.
To OP's question, I really shouldn't have fallen in love with her, for lots of reasons. But I also should have and am glad I did because it enriched us and left us each in a better place. Feels good to share that story.