[Career milestones and relationships] I am not sure to keep this relationship or to marry my best friend

I am a 26 yo 5'11" 320# male, and chubby myself. I started going to the gym and I started lovin' it. I got married 2 years ago, I am dating my wife since high school, I am in love with her since I had met her. She is very beautiful 26 yo 5'3" 220# and 170 hip, we were very happy, we were living in an apartment, a one bedroom, quite small. I love my wife a lot, but I was not able to see her a lot of times, she is a pediatrician intern, she is almost always in the hospital. 3 years ago I asked her to rent a bigger house, so we could have a home with 3 bedrooms. She got angry, she said she was quite busy with her volunteering and with her work, and she hadn't time to renovate the house. I told her I'd do it, but she said no. She went a week to help an aunt of hers and afterwards she told me about the home. I didn't like it very much. I went to the gym and I loved it. I started going there 3x a week. I had chubby gains in a week. My wife told me stop going, and I said I cannot, because it makes me feel good and a week after I had my first gains. I didn't expect this. I got stronger and I was spending more and more time in the gym. She told me it wasn't good because she was alone to maintain my daughter, who is now 8 months old.<br><br>One day I met my best friend, we were in the same nursery, we lost sight after high school, and 2 years ago, while pregnant, we met each other at the gym. She was 6 months 5'3" 180# and she told me about her husband, which is a very gentle and kind man, and they have a 5 yo son. She told me afterwards she is divorced and I started to tell her about my life. She told me 2 weeks ago she is a foodie and she loves to eat with a fork and a knife, because she likes to enjoy things, she cannot handle things as she used to when she was young and she quotes the phrase "enjoy the journey" and she said she doesn't like to get fat. I told her I have never been much of a foodie, and I am getting stronger and honestely she looked in love about my words. She had big breast, she told me she was all natural and she was confident enough to let me touch them without any bra, they are so soft and I felt very good when I touched them. I told her I knew something was wrong with my wife 4 months ago and I knew I had to leave her. She started talking about her relationship and she told me she got into a different relationship one year ago, which is with a guy that was 6'4" 450# and he is very nice to her, that she has never been so happy in her life. I have never been so much in love in my life. I honestely know I am going to marry her if I get to, but I know I am going to feel very bad if I am going to leave my wife. I know that I hurt her a lot already, and she is going through a lot of stress and I am not helping her at all. I know that I have to leave her even though she is a good wife, I mean, she is always busy and she is not happy spending her time with me, and she is very honest, too. I have to live my life and I know I am going to die sooner because I am so fat. I want to enjoy the time I have with the people I love. And I know I am not going to keep this relationship, I am going to leave it and I am going to marry my best friend.<br><br>EDIT: deleted to keep this private.