I am so sorry this must be incredibly painful for you.
I have two experiences that can help me relate to this.
One is my own failed marriage to a man who among (many) other problems had a porn addiction and who had never really fancied or respected me I don't think (he once told me I had just made life too easy for him and hadn't made him work hard enough). I had a sexless marriage which I finally left last year and have rather unexpectedly found that I am still considered sexy and loveable by other men (still getting my head round this having bought a house that would be just right for a single ageing me and a squillion cats).
I also know a woman married to a man she never fancied but saw him as a safe option. She married him and had a child but struggles to have sex with him and has already had an affair with a man that she would have left her DH (and taken DD) for but had HER heart broken so stayed with DH (for now). I can objectively say this man IS attractive. He is good looking, fit, funny, faithful, has a good job and is great with the kids and around the house - LOADS of women would be happy to meet someone like him if he was available but he adores his wife.
It must be hideous being a man and having to face the quite real possibility of reduced contact with your children (and I think women often don't recognise how lucky we are in this respect) BUT I think you need to think really carefully about whether you want to spend the rest of your life like this. We only get one life and sex IS important.
You will still see your children and have a relationship with them. Any new woman coming into your life who is worth their salt will appreciate you for that and support you in putting them first. Just my take on it but I think you need to consider the possibility of a happier life for yourself away from this.
You sound lovely, good luck whatever you decide.