I've been married twice--well, allright, 3--but twice to same one! Neither were SDA, but during the first marriage, I wasn't either. I came back after our divorce, strangely, we became much closer and much better friends after our divorce and my return to my faith. As I explained to him---My faith is what makes me liveable! I was an angry woman, due to childhood abuse and we never did talk about it, though I did tell him about it. He thought the best thing to do was to not mention it, thus saving me the agony of reliving it--it was not the right thing to do--so we talked after the divorce.
He met someone new, and so did I. My 2nd I was around 38 and should have known better, but I married outside the faith, he believed in God---loosely, and he was an alcoholic to boot. The hell he put me through for 17 years would take a book--and I married him twice! No fool like an old fool. I did compromise my believes alot. Eventually, taking a stand and going back, but still, even though he has now quite drinking, and we are finally happy together, it isn't quite the same as the closeness you have with another believer.
He doesn't bug me anymore about the sabbath, in fact, He tries to not go shopping and stuff on sabbath, he has slowly learned to pray a little. And when my medical conditions become very painful, he comes in and prays for me---I actually do feel better afterwards.
I have a niece who married another christian, but not an SDA--and I comforted myself with the thought that's it's better to be married to a good unbeliever than to a rotten SDA!! However--she has compromised on everything--they drink, eat whatever--no sabbath observance and so on. Yes, they're happy--but like the book says--what does it matter if you gain the whole world and loose your own soul--or something like that. Bottom line--niether practice any faith.
I've not seen one single marriage of an SDA to an unbeliever to be good for both. And it's usually the SDA that does the compromising.
Not that being married to an SDA when you are one also will gaurentee a happy one. I've seen them break up, have affairs, spousal abuse and so on.
Marriage, no matter what--must be entered into with one heck of a lot of prayer!! And a determination to follow what God says, not your heart--it can lead you astray, God will not. Let Him choose, even if it means remaining single!!