OMG. This is so similar to me. I know how your feeling. I have been married to my husband, and as you stated, we have a nice arguement-free life.
I have been having an affair with someone for three years!! No, it hasn't been exposed. I have tried breaking it off with my "friend" several times but, I keep going back. I cannot bring myself to delete the secret email address and he still texts me too. He tells me that he loves me. I know he will never leave his wife. I would not ask him to do that. I don't want to mess up my childs life by divorce either. We( spouse and I) don't have sex that often. He says he is attracted to me but, I don't seem to be desirable to him That is is the way I feel. When we do have sex it ends up that I have to please him because he can't get me there.
This "friend" is the one that I think about. I do think I love him ..but do I??
As far as the weight gain.. I feel your pain. I was working in a pretty physical job and then went to a desk job. Staring gaining slowly. I am now unemployed and attend college so imagine the exercise there.
I feel so unattractive. But to this "friend" I feel as if he thinks I am perfect.
I know I am suppose to be helping you here...wow how much better do I feel venting here. Sorry about that.
I would like to talk to you more..contact me, if you'd like.

Best wishes
First Impressions