CAR INSURANCE

I don't really understand car insurance. I added Thomas to my car insurance six months ago. Recently it was due for renewal and the quote came in asking for about £10 more a month than I am currently paying. I phoned and told them where to stuff their insurance and of course, with the current business climate being what it is, they decided to try everything to keep my custom. They ran through my details to see if there was anything they could do to bring down my premium. Had I changed where I park overnight? - well no, my garage is still too full to fit it in. Had I changed my annual mileage? Nope again. Did I still want my boyfriend on my policy? Well yes, but we got married so now he's my husband but yes I still want him on and yes he is still the same person... oh well if you got married, that makes all the difference - the policy instantly dropped by £13 a month and came in cheaper than competitors... but why??? He is still the same person, living at the same address and driving the same car in the same manner. How did marrying me instantly drop 20% of my car insurance quote? Is it really that much safer to drive while wearing a platinum ring on one finger maybe? Is he safer now because he now has his mind on the road and not on whether or not I'll marry him??? It truly is bizarre.