Ah the usual santimonious thinly veiled "but what about your health and being a role model" responses.
Firstly, Your DH should help you more with your DC regardless of what you do with that time because she is his child!
I don't think you are selfish not to lose weight and to be honest, even if I lost weight for my husband after such a conversation with him, I don't think I would ever be attracted to him again. Something would have been irrevocably broken. And that would be my prerogative same as it's his not to find me attractive at a bigger size.
He is entitled to not want sex if he isn't attracted and he is entitled to his opinion and feelings around size but equally you are entitled to do what the fuck you want with your body and life.
@SarahAndQuack I think the age comparison is actually excellent because there absolutely are men who do just that: despite botox, surgeries and the best diet and self care they go off to marry a younger woman when the first gets too old. That too is down to attraction.
For some men their taste in age groups will broaden as they grow older... but that can also be broadening the size and body weight range they find attractive. We've all seen pervy 60 year olds still eyeing up teenagers and early twenties and that's just the ones we noticed/caught. How many more secretly and not so secretly also desire a specific age? The fact we have more control over weight than aging doesn't mean that sexual attraction can't also be lost due to aging. We just try not to think about that too much because we can't help aging and we hope our partners have developed enough of a bond with us to stay in the relationship.
OP: I don't think it's selfish not to lose weight for your husband because if you have not got yourself to a healthy weight for your own sake and comfort you likely are in such a bad place the last thing you need is more blame, guilt and shame. But I know some of MNers think shaming is an excellent way to motivate... hence the bad mother insinuations.
op listen to your own feelings on this one and do what you want to do for your own sake. Not for your daughter or your husband but for you. If it were me I'd make him take more responsibilities at home and with our DC and use that time to look after my mental and physical wellbeing and I would see if I still wanted to be with him: the odds are that I wouldn't ever want sex with him again either.