Can a former same-sex partner who helped raise a child apply for parenting time after separation?

Yes. Ontario's parenting law focuses on the actual relationship between the adult and the child, not on whether the adult is the child's legal parent, is married to the other parent, or is in an opposite-sex or same-sex relationship. A former same-sex partner who took on a genuine parenting role - living with the child, sharing day-to-day care, being involved in decisions about their upbringing - can apply for parenting time, contact, or decision-making responsibility on the same legal footing as any other non-parent who stood in a parent-like role, regardless of whether they're a legal parent under Ontario's parentage rules.

As with other non-parent applications, the strength of the case depends on the reality of the relationship: how long the partner was involved in the child's life, what role they actually played day to day, and how the child experienced that relationship. A partner who was only briefly involved, or whose role was more peripheral, has a weaker case than one who was genuinely co-parenting. If this describes your situation, document your involvement in the child's life as thoroughly as you can and get legal advice early, since establishing your role is usually the central issue in these applications.