This thread is like 3 or 4 threads in one and I'm not sure which I should respond to first, but all of these sad stories have touched me. I'll try without judgment to share my own stories and insights. This may be long - and I apologize to all the Pop Daddies out there.
First, to the original OP, I married very, very young at the age of 21 and after 2 years of marriage found myself in an unhappy marriage. I was so religious at the time, it literally starting making me physically sick to even think about any other option. We went to counseling, but my ex was not open to discussing any problems and after 3 sessions, refused to go any further. Within a matter of months, I went from 110 pounds to 95 pounds, was hospitalized with chest pains and breathing difficulties and my 1 1/2 year-old DD's hair fell out. When I heard her pediatrician ask if there were any problems or stress at home that would have caused my child's hair to fall out, that was the turning point. As difficult as it was, I requested a separation and then a divorce. My ex was a wonderful man and father, but a truly terrible husband TO ME - and he was very young also. Fast forward - he has now been happily re-married to another for 20 years, I have happily re-married to my soulmate for 15 years and we've been together for 22 years. My ex and I, and our spouses are still friends and my DD grew up well adjusted and happy. We all go out to dinner together and my current MIL even vacations with my ex-MIL and my ex every year. My divorce was a true blessing for all or us. It's not always the horrible thing some make it out to be.
Meanwhile, my brother has stayed in a loveless marriage for 25 years. A few months ago, after a family function and a few bottles of wine, my brother confessed to us all (and his DD, my 23 yr-old niece included) that he and his wife had had no connection in years and had not had sex in 6 years, but that they should get credit for holding it together for 25 years. My niece was so distraught, and said "Dad, you didn't do us any favors and I wished you had broken up years ago. I don't ever want to be in a relationship with anyone if this is what it is going to be." It broke my heart.
But, to the original OP and to Snow White, your marriages don't sound loveless, so I would recommend working on them through counseling and better communication. Sometimes open communication, confrontation and support can make all the difference and I wish both of you the best.
To those with the affair questions, I will not judge you. We are not in your shoes. My DH's business partner is cheating on his wife, but because I do, unfortunately, know both the personal details of his marriage both from him and his wife, I totally understand. Neither one will divorce, and they admit they don't love each other and each has chosen to select other recreation partners. Although it would not be a choice for me, I will not criticize them. But, their kids are having all sorts of physical ailments that I'm sure are stress related. I hope those of you who find yourselves in that position find either some peace or solace or else a way to end your own unhappiness without hurting others.
Meanwhile, I just came from a funeral of a 44 year-old friend from an aneurysm, am upset, and if I'm too melancholy for this thread, I apologize. But, to all of us who have wonderful marriages, don't EVER forget to let your DH or DW (and kids) know EVERYDAY how incredible they are and what they mean to your life.