what kind of a jealousy is it? there's loads of types.
lots of people seem to have assumed you mean the kind where you are afraid they'll go off with someone else. myself, I suffer from the kind where you just desperately want to be there with them & are jealous of the fun they're having that you could have shared.
the only cure for that one is to make sure you are together as much as poss - and try to enjoy their fun 2nd hand if you can;t be there. talk together about what you've done apart - share the memories that way.