What if I'm love with someone other than my husband?

I am 26 and have been with my husband for 10 years now, of that we’ve been married 4 years. But i im in love with another man. The problem is, i went out with him before i met my husband, and we were very happy, the he broke up with me (or so i thought). I was heart broken, ‘couse i thought things went well. Years later, i still had the same feeling for him, but was now engage. The i got married, and about a year after that, we spoke about what happened, and it came out that is was not him who foned me. And he got a letter telling him that im braking up with him. That defistated the both of us. So…, we are actualy still together. I’ve been seing a bit more of him lately, and he tol me that he’s feelings are also still the same about me. I dont know what to do! I have felt so much for him for years, and got married, not knowing i still had a change with him. On the other hand, my husband and i have had so much problems in the past, and got to a verge of divorce, but i fought it, couse i am so scared of being alone. I feel so diffarent when i’m with Mr. X. and i cant stop thinking of him. I would just start cruing out of the blue, couse i cant be with him. I feel traped. Please help.