Well, I hope that glammanana is right, Valdraree27, but to be honest, I have found that jealousies of the "other" grandparents come up all the time. Next year, for example, my daughter and son-in-law, plus two children, are taking a fortnight's holiday en famille with the "others" and their other son, daughter-in-law and two children, in Thailand. Well, I am jealous of that, since we never get so long with them ourselves. On the other hand, I am not certain I should want to...
The point, really, is to accept that a) you can be jealous; b) that sometimes there is good reason for your jealousy and c) that no good can ever come from expressing it, except in private to one's husband and you lovely Gransnetters. That way, you can accept and deal with your feelings, and remember, all the time, that it is the strength of your relationships with your offspring and grandchildren that matters - not the strength of theirs with the "other" side.
Thankfully, I have great relationships with my daughters and grandchildren, and, although I don't particularly want to acknowledge it, I know that they benefit from having great relationships with the others as well. Then all I need to remember is that I want the best for my descendants!