Many people have asked about same sex applications. Canada has long had an enlightened policy. Until recently these applications fell under the Independent (now Skilled Worker) category. If you have applied under the old system and asked to be considered on Humanitarian and Compassionate grounds I understand those applications will proceed as before. By now most of the older cases will have been processed. New applications now fall under the Family Class category.
If you are called for interview as part of the Family Class application try not to worry. Take evidence to show your relationship. Photos, cards, letters (they won't read your personal mail but have it there as evidence of the relationship). Telephone bills are good too as are joint bank statements, bills, lease or rental agreements. Your application will be treated impartially and fairly, there is no discrimination on this basis. Heterosexual spouse/partner sponsorships are equally scrutinised.
For useful information on this subject go to LEGIT. I really strongly recommend this ornagisation for all kinds of resources. Like my site they are not commercial and are there to help. It is run by volunteers.