Hi Jeff,
I am Canadian, sponsoring my American husband. We were married in the U.S. since he is not able to come to Canada until his PR is approved. Our marriage is considered legal. I have been approved as sponsor and the file is currently in Buffalo, awaiting approval of the next stage.
I agree with the previous posters. Marriage is the best option to apply under. I also don't think that a lawyer is necessary. While the forms may seem daunting, once you start completing them and collecting all the backup documentation to prove the relationship, it will not seem so bad. If a lawyer completes them, you will still have to provide all the information required anyways.
Some pointers, document the development of the relationship in great detail, including any emails/IMs/phone records/SKYPE that you have. Cards exchanged and photos, especially of the wedding are needed. Supporting financial records (you can read details in the guide) are important.
FBI fingerprints records are good for 90 days but can take up to 13 weeks to get back from VA so timing is important.
The medical is good for a year so again timing is important.
Any questions you have, members here are to help, we've all been through it.
Welcome and good luck.
EDIT: I MEANT 'NOT' NECESSARY. must have still been half asleep. Sorry