I can't choose between them

Soo my bf and i broke up after being together about 5 years. I found another guy, who i started dating. I cheated him and decided to broke up with my bf. I enjoyed being singel and my time with the guy i cheated with, because i liked there were no obligations. For a while it was fun, but i was having a hard time forgetting my first bf, because i really loved him. So we ended up together, and we still are and love him with all of my heart.
But the guy i cheated with was always my minds. I couldn't get over him. And it turns out, he couldn't too. After a while he texted me and asked to meet. At first i didn't told no, but his talking and flirting skills got me, and we ended up bed. After that I though thats never gonna happen again, but it did. He was in the relationship at the time too. After many girlfriends he ended up me again and again. But my relationship with my bf was going great too. So i cheated my bf with him all over again. And im still doing it, after 4 years. What should i do? I can't choose between them.