There is no real right or wrong answer, as the definition in CIC guide here is pretty vague: http://www.cic.gc.ca/english/resources/manuals/op/op02-eng.pdf
5.35. What is cohabitation?
“Cohabitation” means “living together.” Two people who are cohabiting have combined their affairs
and set up their household together in one dwelling. To be considered common-law partners, they
must have cohabited for at least one year. This is the standard definition used across the federal
government. It means continuous cohabitation for one year, not intermittent cohabitation
adding up to one year. The continuous nature of the cohabitation is a universal understanding
based on case law.
While cohabitation means living together continuously, from time to time, one or the other partner
may have left the home for work or business travel, family obligations, and so on. The separation
must be temporary and short.
It sounds like you were living together 14 months, and during that time you took a 3-month trip to Spain. Of course trips apart for family, business etc are fully allowed, the only question is if 3 months would fall under the definition of "temporary and short". Since there is no specific time given, it would be up to you to argue the case or not. You would have to say you did not go back to Spain to "live" and set up a new household there, you went on vacation and stayed with friends/family.
IMO if you could provide evidence and show that you had truly established a household together in Canada with your partner, then you could qualify. You would need to show things like joint finances, joint lease/rent/mortgage, joint household utilities, joint household expenses, joint purchases & household management, important documents being delivered to house, etc etc.
Of course there are no guarantees. In the end its up to the VO that reviews your file if they will accept your trip as temporary and accept your common-law status, or if they feel the 3-month trip apart broke the "continuous" cohabitation rule and force you to start over again from the day you returned.