shearlove, mariposa's comments make a lot of sense. I, too, wish you the best but in recognizing that your fiance has struggled with his addictions in the past, it would be naive to think that he WILL never struggle again. Addiction is an illness. He could relapse. Hopefully, he will maintain a strong enough desire not to as well as a good support system to help him. As his partner, you should make sure that you, too, have a support system.
Living with an addict, even a recovering addict, is not easy. It is an illness and relapses happen. If your fiance had diabetes or a heart condition, you would prepare yourself for a serious illness or heart attack. You should do no less as the partner of an addict.
I think that you should follow your dreams...always. But, do so with your eyes wide open and with contingency plans in place so that YOU don't end up in trouble.