Hi CuriousAboutTime and welcome to the forums!
In Ontario, you have to live together for 3 years in a common law relationship to be entitled to spousal support. The 3 years needs to be continuous. If you had broken up for a few days or weeks, that might not make a difference, but 15 months of separation would certainly end any continuity.
However, I note that at one point you lived together for 40 months. This would create an entitlement to spousal support. It gets a bit more complicated here. If you broke up from that 40 month period before January 1, 2004, any claim for spousal support would be extinguished (see:
http://www.ottawadivorce.com/forum/s...02&postcount=2 for more details). If you separated on or after January 1, 2004, then the claim would still exist.