Proper protocol for leaving a job (UPDATE IN OP)

Here's the deal:

Received an offer to begin in a field 6 months ago with no background.

Great opportunities were presented at initial offer. Come into the field (insurance) and kill it. Write more policies in two months than the rest of the office staff for that same period combined. Lead team to two of the best three months my agent has ever had.

District manager comes and takes me out to lunches on a regular basis. I like the DM, but my agent and I don't get along at all. We butt heads constantly, and he has little patience.

Got headhunted by a competitor the other day who offerd a 15% raise and a great opportunity to lead her sales team.

I have only been on the payroll for my current employer for 6 months.

Uncouth to leave? My leaving will devestate his office and the goals will not be met this year, but should I show loyalty to a boss who I serve in a thankless manner? Is it unprofessional?

P.S. He is out of the country until next week and when he returns I plan on putting in my two week notice, but don't think it will blindside him.

P.S.S. I don't think he'll match the offer.



Update- Upon my boss' return we sat down and I explained the situation for him. He nodded his head, said that I had to do what I had to do, asked me who the company was (I told him), then asked me when was the last day I would work for him. I told him two weeks. I go back to my desk, finish out my day (which included running all over town doing underwritingesque work, get back to the office, and he tells me to pack my stuff.

He did bring me back a Scotish scarf from his trip though!

Took a two week vacation and started with my new company on Monday. Thanks for the advice people.