h1b - i140 withdraw and revoke?


I am on H1b valid till Nov 2016(completing 6 year). My current employer has filed for i140 and got it approved.I have job offer now from a different company. Correct me If I am wrong- I think i should get another 3 years when my h1 transfer is done to new company. What are the implications if my current employer withdraws or revokes my i140 after I move to new company. Is withdrawing and revoking i140 the same? Is it possible to use the same i140 for another 3 year ext with all future employers?

Also my spouse has not applied EAD so far. Planning to use the EAD feature may be next year after making job move. Please suggest.