In the "old days", it was true that an often reported comment by surgical PDs was that the "best resident is an unmarried resident". It probably goes without saying that they also thought the best resident was male.
The reasoning was that married residents, especially those with children, felt a pull AWAY from the hospital and might otherwise be distracted by family issues.
And while this may be true in many cases, I think most PDs don't really care either way these days. A happy resident is generally a good resident...so if you're married, and your spouse works, they might be interested in knowing that he/she has gainful employment opportunities in town, and if you're single with an SO, the same applies.
I generally was interested because I thought my program had room for both married and unmarried residents and also because if they did have an SO coming along, almost always (especially if the SO was female), what SHE thought about the area was important. Frankly, if you're applying to Cali programs and your SO is from Florida and very close to her family, I might wonder if you would be a good fit here...not because you're married but because the location is not ideal for your SO.
Bottom line is that its a) illegal to base matching decisions on marital status and b) I rarely ever heard someone mention it during ranking decisions except when the situation above arose (or the opposite..."his wife loves it here apparently"). I wouldn't worry about it...be honest and forget about it.