About your birthday, I understand that you feel enough is enough and you want someone else to organise this. Have you told him that you would like to do something nice but would like a surprise?
I know you want him to be thoughtful enough to consider it himself but I feel if you haven't told him then you are setting him up to fail and yourself up to be miserable. If you are the family organiser who would normally organise things that you would like to happen, but you haven't organised this and you haven't told anyone that you'd like them to organise it - it would be reasonable to assume that you didn't want to mark your birthday, plenty of people shy from making a big deal of milestone birthdays.
Its setting someone a secret test which they don't know about, which you will then judge them on and either feel quietly miserable about "If he really knew me and loved me he would have organised something for my birthday" or possibly even throw back at him in a later argument "You didn't even remember to do anything for my birthday!"
I don't think its fair to do this to him, and I don't think it will make you feel any better about the relationship.
Likewise, you've said that children are naturally selfish and appear to be martyring yourself to them and your husband and then feeling miserable about it. I think you need to be clearer about your expectations of everyone, they should all be able to treat you with age-appropriate respect and consideration - in the case of your husband it should be equal to your own and the children should be learning.
I'm not saying its all your fault or that no one else needs to change. I agree with much of what has been said already about your DH needing to be more considerate. But I think you need to tell people how you feel about what they do, otherwise they will assume you are fine with everything.
I don't think you are a terrible person BTW. I have a tendancy to do this too. I have an idea in my head that people are slighting me because they haven't done x, y or z. I feel miserable about them and me. If I eventually raise it with them, they are usually apologetic and confused, they didn't realise what I expected. People can't mind read what you want. And you can't mind read their reasons for not doing what you want. I've had to learn this myself and remind myself of it.
You need to learn how to communicate your feelings and expectations to your partner, through councilling if necessary. If he still doesn't respond then maybe your marriage is in trouble because he ought to respond to your unhappiness (though it may be a compromise rather than everything you'd prefer).
It sounds like you are the level headed one in a crisis. Not everyone is like that naturally. If he's always seen you as the strong, together one, it isn't surprising he's been leaning on you, but you maybe need to point out that you were scared too and you needed him to be strong also about the ambulance. Hope your boys are well now.