Does Spouse need to get WES evaluation done if applying under Express entry and i am the primary applicant?
It is
not mandatory for your spouse to have WES evaluation.
For the Primary applicant it is required.
But... If you want to claim additional CRS points from your spouse educational background, you have to submit the her ECA report /WES.
Imho, I will always suggest to get ECA for spouse if possible. Who does not want additional points to increase CRS standing making it easier to get ITA?