I'm about to break up with my best friend, when she thinks I'm going to propose in March

My Partner (F30, We'll call her J) and I (M34) have been together for 9 year in March, we're in the middle of planning a trip to Japan and the harder sides of the relationship have just gotten too much. We've had a dead bedroom for 8 years of the relationship due to some unfortunate circumstances and then a lack of reconnection even though I've tried so hard. She is my best friend, other than her ability to show me physical affection in the way I need it, I have nothing else to complain about. She's better than me in every way, I'm so lucky to be with her otherwise. She fits into my life perfectly. She's able to be as bogan and down to earth as my extended family, but is elegant , intelligent, witty and beautiful when with my parents and their friends who are quite well off. I love her family, I want her mum to be my mum, I have already asked her mum for her hand and she was so excited. I've put on weight because I feel so physically unattractive and there is no reason to try. I've work on so much with my self to better who I am, make more effort around the house, do everything she's mentioned in couples councilling. I'm losing the best part of my entire life, without doubt. But I'm just so lonely physically. I feel so selfish. I've moved away from my home for her, then moved back to her home for her. I've devoted myself to her. I just want sex and to not feel ashamed of myself for that. I can't do it before Christmas, I wouldn't do that to her. So I have to wait until after we get back. So I've got to go through a family holiday and Christmas knowing this. It just clicked today. I hate myself. Edit: So to be clear, the two traumatic experiences meant starting a new medication and a depressive episode which killed her Labido. They were a cyst bursting requiring a Laparoscopy and her father confessing he was cheating on her mum to her of father's Day. Then left it for her to tell her mum. Which I helped her do and walked away once the conversation had started to give them privacy. We had fantastic sex before this happened. Edit 2: just to make sure. I have made this clear both in and out of couples therapy that this is something I need as part of a relationship. I've begged her if she can't fix this, to please just let me go. All of this over the last 7 years. Final Edit: thank you all for your thoughts. It's nice to know the 74 different things running through were all valid.