My 2 cents again, for I lived it....DON'T DO IT. Marry someone who believes the way that you do, who attends the same church. If you don't, you are asking for even MORE work to make a marriage relationship a happy and healthy one, and that no matter HOW MUCH work you put into it, will still have a huge chance of not surviving.
Most will say, when their relationship is new, and they are leaving each other breathless from just looking into each others eyes, that "it doesn't matter what church we go to". Believe me when I tell you they mean it sincerely too...UNTIL....a baby arrives, or some other life altering event that sends one deeply into their religious roots and contemplation.
Honor is right. There are too many differences between SDA and mainstream that is BOUND to cause problems. As I have stated before, I could NEVER go back to a Sunday keeping church and be happy. I would always feel, in my heart, that I was disobeying God. I would have no rest.
As Honor said, marriage is tough enough as it is...you will GREATLY enhance your chances of not only side-stepping divorce which runs rampant today, but of having a blissfully happy marriage that truly does last til death do you part.
There is something else to contemplate as well....the odds of both people attending their own respective church services...and each one CONTINUING to go alone, are not good. Usually, one or the other will simply not go because they don't like going alone and fielding the "where's your husband/wife questions". Petty? Not if you are the one experiencing it week after week.
Honor, you are the one I usually turn to when I have scripture in my head and can't remember where I read it...I'm not sure I ever read this one, but I remember my father, when I was growing up, talking about how God intended us to stay within our "tribes" as far as marriage went. Did he get that from scripture? He always said, "God didn't intend for us to 'mix' in marriage".