Three years ago, as a woman in her mid thirties, I posted on Mumsnet with this exact dilemma.
I had been with my bf for 8 years I loved him but anytime I tried to initiate sex, he shot me down. In the end I stopped trying. Confidence hit a rock bottom. I lost weight and tried different things, tried to talk to him but he wasn't interested. In the first couple of years, things had been great - but over the years, he became less interested. In the end we were doing it once every two months and he'd never finish. It was miserable. I accepted I'd be in a sexless relationship forever. I asked Mumsnet for advice and to my horror, many people said to leave whilst I was still young. Some said they had been in sexless relationships for 10 or 20+ years and wished they'd left sooner. Others said they wished they'd left before they'd had kids. Many said they had left and it had been the best thing they done. I was in so many minds.
I didn't do anything for a few months because I loved him and thought maybe things could change.
They didn't change.
I tried to talk to him again and he said this was the way it was and he wasn't ever going to change.
I didn't sleep for a month or so after that conversation as I knew i had to leave. I went back and read all the lovely comments the Mumsnet community had left me. One day I said I couldn't live a life like this anymore. He didn't even fight for it. Just shrugged his shoulders and said something asking the lines if 'fair enough'.
I bought several new outfits and immediately went out. Had sex with an old friend within a week and I felt absolutely brilliant. I felt alive again. I knew I had it in me. I was scared but I sat with the scared feeling and just thought "F@?& it. I deserve a full life and to me - sex is a big part of that."
I have never regretted ending that relationship. So much of it was great but the 'no sex' was a big white elephant that was ALWAYS there. You can't ignore it. Go with your gut. You will feel scared but you owe it to yourself. The future you in five or ten years will be so proud of you. Don't settle, you deserve a full life as well. X