I feel so alone in my relationship

I feel alone. We only have sex once a month and it’s me basically begging to have sex. We never miss, unless I kiss him and it’s an awkward distant kiss, no tongue. I’ve been with my boyfriend almost 9 years and we have a 3 year old. He refuses to marry me because he doesn’t believe in marriage. He told on on my birthday when we were drinking that he wasn’t attracted to me at all. I don’t know how to fix it. I want a family so bad for my daughter and I hate the idea of being a single mom because I grew up in a home with so much love. My father fawned over my mother for 25 years until the day he died. I love my daughter more than anything and I want the best for her. I don’t know what else I can do to make this work with this relationship. I feel like his roommate. When he smoked our relationship was always better, I think it makes him happier. His job doesn’t allow him to smoke and in the 3 months since he quit it seems like everything in our lives are falling apart. I know I’ve gained weight and he’s told me I have. I’m doing everything I can to get rid of the weight but it’s so hard. I’m a size 12 and in California I might as well be 300 lbs. I’ll never be good enough