Did you have a discussion with your dp about whether it would be you or him?
Last week my dh said 'well I'm not giving up my job - no discussion'. Obviously he's being a bit of a twat but having stewed on it now for a week it's still really bothering me. We earn roughly the same salary.
I would prefer to have one of us look after the DC (like him) and not be inconvenienced when they're ill and unable to go to cm (like him) but why should it be me that gives up work?