Actually, depends where they are in the country, £22k in the South East is not a well paying job, it's about £10k less than you'd pay a receptionist in most of London. I think we have an office junior on about that.
The general lack of innitiative is going to be hard if you're different - feeling you have to "mother" your DH as well as your DCs is poision for a relationship unless you are the sort of person who likes to take that sort of role. You aren't the first person who's found differences in priorities/attitudes, while not a big deal before DCs come along, are a huge issue once they are there.
Do you generally feel he's not pulling his weight? Not just income, just generally in the relationship? Would you feel comfortable that if he went 4 days a week, when the DCs were at school/pre-school that day, he'd do the other household admin without you requiring to leave him a list of things to be sorted/thought about?
Is it that he's happy to do what he's told too, but not think about what might be useful/needed?
Some times that can be changed, little by little, but it's going to be a long slog, only you know if it's worth it, but staying as you are, you'll get more and more annoyed and it'll ruin what you've got if you're losing respect for him. Few marriages survive once one side has lost respect for the other.