If you say that, it means you got married 10 years ago and you are still married. Of course, it is possible that this current marriage is not your first one, and that you got divorced some time more than ten years ago. But based on that sentence, you are still married to the person you married ten years ago.

I was married for 10 years. Then I got divorced. The way you phrase it gives the sense that you are still married.

If you say "I've been married for 10 years," I assume that you are still married. I am not certain if the sentence has an ambiguity. If you want to convey the idea that you are divorced now, one simple, short, unambiguous phrasing is "I was once married for almost ten years." "Was once" indicates that you are not married now. If you want to convey the idea that you are still married, you could say "My wife and I have been married for ten years." By including the word "wife," rather than "ex-wife," you convey the idea that you are married now, to the person you have been married to for ten years."

to throw my idea in on top of the others: "i HAD been married for ten years, then I got divorced. I have been happily married to my second wife for 10 years"

Claire and Karen gave excellent answers. If you have English Grammar in Use by Murphy, consult Unit 11. Excerpt: Dan and Kate are married. They got married exactly 20 years ago, so today is their 20th wedding anniversary. They have been married for 20 years.