If loving him is wrong😢

ok so this story starts about 5 years ago, i met a really awesome guy at a party, and it was an instant connection. like just talking to him gave me butterflies, i could see our future together flash before my eyes in the firsr 3 hrs of us hanging out at the party. But some things are too good to be true, so after a " i have a girlfriend and im not ready to leave her" my heart broke a lil but i was moving in a few weeks so i told myself i can have a lil fun (wrong, but i rationalized with myself he isnt married, so hes single)  so it begin, meeting up hanging out and everything in between. Several weeks in bliss, and then just like that i spent one more night with him and the next morning i move to another state. That should have been the end of our story, but it wasnt. So initially we kept in touch text messages here and there, but after a while life happened and we just didnt speak i mean, i was in another state and he was in a relationship. So i stayed out of state for 3 yrs, and due to circumstances i had to move back to my home town. About a week after i got back we got in touch he was still in the same relationship but claim he wasnt happy and months after that he started telling me he loves me. Honestly it took almost a year to say it back because i thought i was playing it cool and keeping my emotions in check because i knew he had a girlfriend. But i did it. I fell in love with him. In the beginning i never asked him to leave it didnt matter to me. (Because i was playing it cool remember smh lol) But the more he showed me he loved me the more i wanted him to myself. I have met his whole family and all of his friends and vice versa. But it still breaks my heart when he leaves me to go home. I have tried to break it off, but i have been dramatically unsuccessful. He gives his reasons for why he hasnt left her yet. And i know its because he loves her more (well that's how i feel) but i stay. I already wrote alot and its so many more details to this ugly triangle. But i just needed to vent. Thanks for reading.