What is preventing you from fixing up your apartment? Are you waiting until the two of you get married and move into a house together? Do you lack the money? Do you love him and wish he was "the one", because he is a fine man indeed, but deep down in your heart of hearts and soul of souls, fear that it might be a mistake to marry him?
Do the two of you experience mutual simultaneous sexual pleasure in equal measure when you are making love? Or do you feel that sex could somehow be better? Is the condition of your apartment a subconscious manifestation, indicating that something is missing in your relationship?
Of course, I'm projecting all over the place. I always think sex is the bottom line in a sexual relationship because it is for me.