Need Help

I am 38 and I’ve been married for 12 years. I met my wife where I was working and on our first date she became pregnant. Yes the child is mine. I did what I thought was the right thing to do and married her. I never had the butterflies in my stomach head over hills for her feeling. We’ve always got along and I can count on one hand how many times we’ve had a fight. Our relationship was built out of stress that we’ve overcome and over the years I’ve grown to love her. Since we’ve had two more children (twins). Over the last year I’ve become increasing bored of my mundane life with the day in and out routines. I’ve built a successful business and a “picture” perfect life. Inside I’m depressed and unhappy. I couldn’t bring myself to tell her because she seems to be perfectly content. We have sex maybe 2 or three times a year and I find myself only doing it to just get it over with. I recently went out of town and met a woman that I have an amazing connection with and after a short while of being around her I made the mistake of kissing her. I feel like the worst person in the world and I can’t believe what I’ve done. I severed the communication with the other woman even though I feel I lost what could of made me happy. The sheer thought of what that would do to my children is what made me not take it any further. Not to mention my wife is truly a wonderful woman and dose not deserve what I’ve done. This whole ordeal has made me realize I am unhappy with my marriage and I don’t know what to do. I do love my wife I just feel like I love her more as a friend if that makes any sense. I want to feel the way I felt with the other woman but with my wife. I also wonder if this is some kinds of mid life crisis. I don’t have the terrible marriage where we fight and I sometimes hate her or anything like that I just feel lonely. I don’t have anyone to talk to to tell me I’m just being an asshole pos or tell me I’m not alone......am I ?