You can be outside Canada for up to 3 years in a 5 year period without losing your PR. If you stay out for all of the 3 years completely, you can not leave Canada at all for the next 2. That is the way it works.
Some more options.. husband goes back to work, you all stay for 3 years, get citizenship and then join him. Once you, a citizen will have lived with him for 2 years, his PR will be re-instated as a PR will meet the residency requirements if he is staying with a Canadian citizen spouse overseas. Or you decide to stay but after 3, 4 or 5 years, your husband decides he wants to join you again. He will have lost his PR but you either still have your PR or have citizenship already so you can sponsor him again.
Or you land, all go back to KSA and then decide last minute after almost 3 years if you want to move to Canada to meet your requirements or skip it. If you keep your PR alive, you can always sponsor the husband later if he loses his and same with the children as long as they are under 22.