Can an ex get support if she was never common-law?
No. Under Ontario law it is only “spouses” who are entitled to obtain support from each other, depending on various factors such as respective need and ability to pay.
Naturally, you qualify as spouses if you and your Ex are or were legally married. Likewise, you will be considered spouses for these purposes if you met the legal threshold for living in a common law relationship. (The requirement being that you have been living together for at least three years, OR you have a child together and have been living together in a relationship of some permanence).
But if your Ex was neither your spouse by marriage, nor your spouse under this common law test, then he or she is not entitled to spousal support.