Was I a fool?

I fell head over heels in love with a married man, gradually. It began as friendship and eventually blossomed (so I thought) into a romance where we began to have very strong feelings for each other. I was really mislead and developed very strong feelings for this man, that told me the same. All of a sudden, he told me he can't see me anymore since he cannot dishonor his wife, whom he loves. He sent me away and I feel like he opened the door to his heart, let me in, I gave him mine and now he is throwing me out of his heart and returning mine... all without warning. I feel so heartbroken. Was I a fool? How do I move on. He is all I can think about and I still feel such strong devotion towards him and only nim.