"I'm here providing a sympathetic shoulder for him to unburden his problems on. But what he doesnt realise and maybe you don't either is that by doing that he stresses me out aswell. "
Having re-read this, it makes me feel even more certain that financial, rather than emotional, support is what your DH would appreciate. Yes, we all need someone to offload to at times, but tbh with him working from home, and you being at home getting more stressed out by hearing his worries, is not doing either of you any good. Believe me, you don't stop being a listening ear just because you're not at home all day - plenty of couple both work and continue to provide emotional support - that's just being married!
diddl makes a good point - I imagine your DH sees the future stretching ahead, and maybe another decade of having to be the sole provider. If you are saying you couldn't get a job even with your older two in school, then presumably its not going to get any easier with the third child. So you could be looking at 20 or so years out of the workplace, after which time you're going to (realistically) find it very hard to get employment in anything other than very low paid, mundane work (which you probably won't want to do, as you're already fed up of the routine grind of housework).
I am guessing your DH threw that rather barbed comment in the heat of the moment, which is unkind, but it reveals his deeper feelings of anxiety about having to carry so much financial responsibility over such a long period of time.
I would sit down and discuss how you can plan to have a better balance in the coming years. Don't feel that he needs you to be home 24/7 just to provide a listening ear. Sometimes, dwelling too much on worries can magnify them anyway, and its better to talk less, and take practical action instead