I would be upfront as soon as you can. You are losing sleep, wishing things were different, and living a false life. My ex and I didn't have sex for three years, and he shut down about it. I would say, "we need to have sex again," and he would agree but nothing would happen. It broke my heart. Then one day he told me he wanted a divorce. Atleast if we had made some effort during those last three years to fix things, splitting up would've been easier, or made more sense. But to stay in limbo, no movement, stagnating, suffocating - you deserve better, even if the movement you take is further apart.
Tell your primary you are tired of walking on eggshells around him. Don't hold back your tears. He needs to open his eyes, he needs to hear you, and to talk, no matter how uncomfortable it makes him. This is your life. There is a big issue here that needs serious confronting, and it is hurting your relationship with him and with yourself. Then spill everything and face it all. See where it takes you - whether the remedy is medical (he should get checked for testosterone levels, which can be supplemented), or emotional (therapy, splitting up, etc.), you need it now. Your spirit needs it.