US/Canada tax returns

Hi, here are some of the facts:
-I am a Dual US/Canadian Citizen
-I work for a Canadian company, pay Canadian income taxes. I work via my computer in Texas, just like I would if I was at my desk in Canada.
-I live in the US (at least I am in the US 80% of the year, heading back to Canada once a quarter)
-I am married to a US Citizen who has no ties to Canada, and has US Income

How should my taxes be handled?
-should I still be paying Canadian income taxes on my Canadian earnings? (yes, it's a Canadian company, paid in Canadian funds, deposited into a Canadian bank account) However I am doing the work from my desktop in Texas.
-where should I still file taxes? in Canada? in the US? both?

Is the only way to figure this out to fill out a "determination of residency status" form with the Canada Revenue Agency?

Help! this is so confusing even tax professionals here are having trouble with it...

Additional facts:
-when I came to the US I did not intend to stay, or at least I did not know what would happen. Then my job said they would let me work via computer from the US so now I only go back about 40 days a year. It has now been about a year, and I filed my last tax return in Canada as a Canadian resident not taking into account any of the US stuff
-my wife in the US files quarterly returns and right now I am being included in that US tax return filing and the tax prepares are trying to figure out how to handle it. They have a copy of my pay stub.

How should this be done? Should I not file in Canada, should I fine in Canada, and then use those tax payments to offset any taxes due in the US once I file here with my wife? huughh

you've asked at forums.serbinski.com, so don't expect any different answer here. That is the gold standard source.