First of all, you don't need a comma in either one. You would only need a comma if you placed the dependent clauses at the beginning of the sentences. The second one makes it clear that that the fact that she was married was seen as a drawback or a problem-- either by the subject or by the writer or speaker. In the first one, the writer could be implying that the subject prefers dating married women.

To my eye, they mean the same thing, and I like the commas, even if they're not needed.