I Fell In Love With My Best Friend

•Teenage Love Affair•

My story starts back when I was only 13 years old. My mother, a year after having a nervous breakdown, decided she didn't want to be with my father anymore...so she packed her bags and moved my 2 older brothers and her to another state. I was devestated. It was just me and my little sister that was left to be raised by my father who, at the time, said he wanted to have us...but he was always gone.
Partying, drinking, and staying out all night with other women. I raised my younger sister, and...I had really low self-esteem problems, always getting picked on at school and such.
The day I decided I was going to go through with the suicide plan, this boy (lets call him Mark) at my church, took a huge interesting in me. The first time a boy ever flirted with me, even paid attention to me in any kind of way, I was perplexed.
Time went on and we grew up, and throughout 3 years we talked, made out, hung out together, everyone thought we were a couple...but we weren't. He had his girlfriends, and I had my boyfriends, but when we were together it was like it was just us and nobody else.
I left for a year and a half and never told him until the day before I left. We lost contact...after 8 months I got out of school and I moved with my mom, in a different state. We talked when I was down there and he told me how much he missed me and truthfully, I missed him too. I came back January of 2004, but he had a girlfriend when I came back, so I got a boyfriend. We were intimate for the first time ever 4 years after we first started talking and then again a month later.
Five months after that I met my husband and moved in with him, 4 months after that I got pregnant with my oldest daughter...I got pregnant again and got married...I lost touch with Mark and I figured he had moved on until he found me on myspace. We talked and pictures were exchanged and my husband and his wife found them and the messeges saying how much we missed each other last year, and we stopped talking for a while after that, but...we have this strange attraction to each other, and he wrote me on yahoo messenger and we started talking again.
This past September we cheated on our spouses with each other, and then he lost touch with me because my phone got turned off, and he is in the Navy, so he had to go overseas. This past February he told me he loved me for the first time and just last week he told me he missed me so much.
I am still in love with him, but I am married, and he is married. I never thought I would be the woman that would be considered "the other woman" in a man's marriage, but here I am. Joining this group because I loved a boy that turned into a man that is married.
I just don't know what to do. Any advice would be welcomed.