The "why not" is to protect Canadians from losing their jobs to non-Canadians. Think of what would happen if anyone from anywhere in the world could come take a job with no requirements. Doctors and lawyers would be getting paid minimum wage

.
But seriously, you are a web developer. Just stay as a visitor, do some freelancing or get some online clients outside of Canada, or a remote job from Spain. You can work remotely as long as you aren't working for any Canadian. My husband and I travel all over doing that. Yea it's not as easy as having a regular job but it's flexible and it would allow you to stay with her legally.
I think Canuck meant, is
she muslim. Because muslims don't usually marry non-muslims. I don't see what she would have to gain from the marriage to make that particularly suspicious though, in this case. There are schemers out there who will marry out of their faith just to get Canadian PR.