Yes, you can after recieving Nomination and before accepting ITA. Make sure to inform Ontario about this change via personal information change form and update your spouse in EE before you accept the ITA.
CIC will mostly approve his application (if he had applied and all other things were fine ) as long as he is not lying regarding this spouse non accompanying thing, I think being honest is more important than making up a fake reason based on many fake immigration "experts" here and in the city