Sorry you're finding it tough, it is very unpleasant feeling rejected like this. I presume your sex drives have not always been quite so mismatched, could this just be a short-term lapse due to the pressures of parenthood and work?
It is my understanding that being put under pressure to perform when you don't feel like it makes most people feel even less like it. It is sad that he isn't in the mood much, but I'm sure equally you wouldn't want him to force himself to go through the motions. In fact, pressing the issue could potentially make a long-term problem out of what might just be a blip.
Are you planning to go back to work? Just asking as you commented he is worried about losing his job and hinted you should return to work. If he is really stressed about where the money is going to be coming from, or resentful of you for staying at home, it could well be affecting his sex drive. Just speculating here, so apologies if I have misinterpreted the situation. Perhaps you could discuss with him ways to help take the pressure off or how he feels about being the sole wage-earner.
In your later post it sounds as if a lot of physical affection is missing from your marriage, not just sex. Would you consider making an effort to give him a friendly massage (no strings), kiss hello, cuddle up on the sofa, etc. If he is not up for any intimacy, even with no pressure, it suggest there is something more going on than just mismatched libidos.