My former spouse/partner has moved in with a new partner. Do I still have to pay spousal support?

Yes. According to a 2000 decision from the Ontario Superior Court of Justice a wife’s subsequent arrangement with a new partner is not an automatic bar to her entitlement to support.

However, it is a factor that should be taken into consideration when an application for a variation is brought. You can however choose to determine spousal support pursuant to a written agreement and then make remarriage or cohabitation by the recipient spouse a condition upon which support may be terminated.