Firstly, I'd like to say that you are a million miles way from being useless, you really are
It takes a certain amount of courage and heart to admit to all the things you admitted too and I don't see a lot of sadness in words like yours, I see some beauty, optimism and hope

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Not giving up on yourself is a key ingredient to success. You touched upon what you see, as sometimes sliding into a depressive state and for some that inevitably goes only one way, but you are seeing a more positive future for yourself and one where your daughter can have more of the person, they already DO deserve in their life and the sort of person I believe you WILL become

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Your husband to humble way of thinking, chose wrongly. To leave you for how you looked is wrong. To leave because a person changes who they are on the inside and becomes difficult to live with and slowly develops a negative personality change over time, is something else.
I don't think you're someone, just from your words alone, that would have become a difficult individual from an emotional perspective to live with and I don't think you are someone that has developed an incapacity to show much human emotion. I think that inside of you resides a person capable of much sunshine and positivity and that your physical circumstances have suppressed that somewhat, as opposed to being someone naturally lacking in such emotional richness.
One of best things you can do, is to recognise that you are that person with that inner potential and not a broken damaged psyche, that cannot mend. The healing process for you, comes not just with addressing your physical side, but the way your mind thinks about you as an emotional person and how you think you are capable of expressing emotion.
I empathise with you, that when you feel in some kind of depressive state, you may not exactly believe, that you are capable of exuding much positivity as a person, even when not in such a state, as depressive behaviour will often overshadow peoples emotional potential, which is very understandable and not thinking well of yourself in such circumstances, would not be a weakness of yours, but symptomatic of the way your circumstances control your freedom to think.
Your courage to speak of your difficulties both past and present, eludes to a certain beauty, that I don't doubt exists within you and it's that quality that will with time, be something that can rise to the fore more and be some form of guiding hand in the way you think about and treat others, not least you and your daughter.
Being an "older Mother", to me should have no bearing on what people think, as age should not factor into the way(s), in which normal, required care quality is administered to a child and whilst unfortunately some people must obviously use age to judge you, they are wrong and shouldn't do it.
I have read enough about you upto now, to know that I don't think for a minute you are going to seriously let your daughter down. Infact some of the best parents are single parents. Sometimes the lack of the second influence is better, because that person may be a highly negative or simply inadequate influence on a child or children, that is counterproductive to the other parents actions.
This statement should be taken as a generalisation however and not a specific description of your Husbands' attitude to your daughter, as it would be crass to make any form of judgement based on 0% evidence.
I think you WILL succeed, because I believe as you say, you have done this sort of thing before and you believe in yourself that it is possible.
So I don't want you to think of yourself as useless, I want you to be proud of yourself

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Proud of admitting all these problems and difficulties and proud of not giving up on yourself and talking about yourself like you are worthless, because there is a difference between useless and worthless and not necessarily being any good at stuff, doesn't mean you have no value.
So you should be proud of yourself and you know something,
I'm really proud of you, for the things I said and you have barely shared any time with me on this forum, except the time since you joined the other day, but you've given me enough reasons through your words and expression, to believe in you, be proud of you and want the best for you.
You're not broken or damaged, you're just someone that has lost some of their ability to shine and express more inner beauty. I know you'll find those things again and be the sort of person, I whole-heartedly believe you CAN be and DESERVE to be and I wish you so much luck trying to find that person

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You ARE worth it and so is your daughter, so chin up, be strong and no worries okay

. If you want this as much as you seem to, you'll make this happen and you'll prove to your daughter what a strong, independant, empowered Lady can be and as for the husband, I'm sure you'll find that inner strength to go on without him and prove that you don't need him to be a wonderful Mother and a wonderful influence on your daughter and if she grows up to be not as you might have liked, don't judge yourself too harshly, but remind yourself that outside influences and TV, play a part too and sometimes with the best will in the world, good people can't be perfect and can't always raise the best kids, but if you do what I believe you CAN do, you'll have every chance of being someone with a child they can be proud of

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It's good to see you starting to take those first positive and important steps to a better future and a better you and we as a community will support you for as long as you want us to

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WELL DONE on being brave and strong enough to talk about your problems and issues and GOOD LUCK again. You CAN do this, I'm sure of that

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