Same story here. Coupled with a ten year age gap (him older) our marriage drifted into a sexless one very quickly. I was naive and inexperienced when we got together. Also, my parents divorced when I was 8 so I'd probably never been exposed to what a true relationship should look, and be, like.
Sex had always been very vanilla and boring (I wasn't stimulated in any way by him and I should never, ever have married him). I do have some sort of love for him but I was, obviously, not 'in love' with him. We lived like brother and sister. We had 2 children (2nd conceived artificially, even though tests showed nothing wrong with us).
I spent most of my marriage 'missing something' but carried on with my career, raising the children and making sure my mum was ok. Yes, it kept me busy, but years later I started to realise that things weren't right.
I wasn't attracted to him sexually. It took me a while to realise that. I felt that I should be and that it was my duty to be attracted to him etc. I think I'd been swept away by him in other areas (he took me away from the council estate I grew up on - mind you, I was on track to do that myself). He was never complimentary towards me either even though other men were, and still are!!He was hypercritical of me, if anything. There was no level of intimacy between us (and, even when there was years ago, it was hardly inspiring). No kissing. No hand-holding. No passion. Nothing. At the end, even a meal out was met with silence and both of us staring into space. No connection. Like a pp said - it was corrosive and soul destroying. I actually, now, well up when I see couples holding hands walking along the street! He was happy to live like that, I guess.
However, I'd accepted it and knew we had a good, secure financial future...but without love/intimacy/affection/desire.
But, life had another plan. Things dramatically changed for me after my mother died and I went through a bad period at work. I also, unbeknown to me at the time, had hit menopause very suddenly at 45. Although, I didn't realise at the time - as I thought my periods stopping had been brought on by work pressures - my whole life was turned upside down. I became extremely unhappy in my marriage (less tolerant and wanted to be on my own a lot) and started to realise that other parts of the marriage were missing - not just sex/intimacy. I also went through the sex surge of menopause (that no-one told me about) and ended up seeking out male attention (and, ultimately, sex and intimacy). Yes, wrong, but I know now why I did it. I became very close to another man who is still in my life to this day.
I went through a lot of soul searching for a couple of years. I felt guilty for feeling the way I did and knew my children would be affected. However, I was also deeply affected and was continuing to be so. I'd been with someone else (wrong in itself) who is/was as passionate as I am and we connect on many levels (yes, we are still in touch by phone etc. but he is also married and in an sexless relationship). I know it was wrong!! We met a few times and have remained in close contact for years. We have agreed not to meet again although it is pretty clear the chemistry between us still remains high to this day. It was never meant to happen but did.
I spoke to my GP and a counsellor in confidence. Both said my marriage was dead. My GP said it was affecting my entire life - which it was - and that I needed to do something. I did. He didn't take it well. I live with the guilt of ending a 23 year marriage with a kind, nice man but he was a man who lacked affection and was cold in lots of ways. And, I felt neglected and unloved. I have been wondering a lot if he has gay tendencies. There is something. He was 36 when I married him and living at home with his parents. Only ever had one, short term, girlfriend. Never saw him interested in other women (on tv, for example), never had him cuddle me from behind etc. But, the biggest decider for me was the fact he had never, not once, verbally said that he loved me. He had never complimented me on my appearance or on my success in my career. He had sat back and let me push forward in mine (hard work) while he just reaped the benefits (staying at the same entry level job he'd got at 22).
I was dying inside. Another man awoke something in me (not just on a sexual level either) and my biggest regret is that I have lived in a sexless/no intimacy marriage for many years. Life pushed me in a different direction and forced me to wake up and take stock. I had to act. I filed for divorce after 23 years of marriage. I hadn't been with anyone else prior to marriage.
I have no regrets but, perhaps, should have done something to end it sooner.
Do not continue to live like this if you are posting here asking for advice. Deep down, you know you are unhappy.