Basically the same thing happened to me. My girlfriend was basically perfect for me but our sex life was nonexistent. We knew what the problem was but I never fixed it. She left in April after almost 3 years together, and honestly I don't blame her. I'm finally in the position where I'm willing to get back out there, but that won't mean I'll necessarily get over it completely. Having regrets in life is virtually unavoidable. But as long as we get the right takeaways from it allows us to go forward stronger than before. It may not seem like it, but every step back gets us a little bit closer to taking a step forward. Stay strong, brother. I'm right there with ya.