I've been with my boyfriend for 10 months now and we've recently moved in together. I love him with all my heart and I can see a future with him. He tells me daily that he loves me and that he couldn't imagine his life without me. At the beginning of the relationship we had a very healthy sex life but for the past 2 months things have changed. He has put on weight and when I've talked to him about it he feels very self-conscious and it has affected his sex-drive.We've been away on holiday, I bought some sexy night wear but nothing happened. I don't know what to do. Whenever I bring it up I get emotional and he get's angry. He's told me as soon as he looses the weight things can get back on track. Despite this I cry myself to sleep most nights as I feel rejected and unattractive. I constantly tell him that I love him but I just don't get why he doesn't want me anymore? Please help.

I think you are approaching this too bluntly. First you have said things to him about gaining weight, and then you have expressed your feelings about being unattractive just because he has backed off on sex. He needs to feel that you like him just the way he is, and he also needs to feel that sex is not an obligation. (Remember that you aren't the one who has to get an erection.)
There might be more, such as a tendency for some men to turn women into their mothers, enjoying their cooking and homemaking (is your good cooking why he's gaining weight?), but we can only guess about that. The pressure you are putting on him is your number one problem for now. You need to drop the notion that you have to have sex just to feel attractive, you need to stop saying anything about his weight. If bolstering his self esteem doesn't work in a month or two, and good communication about feelings isn't happening, then see a counselor.