Always in the back seat

My wife and I have been married 23 years, like everybody else we have had our ups and downs, but all said and done you get on with it. Anyway I am 53. My wife is 45. 5.8 145lb. brunette. From when we met and started having sex, she always insisted about getting in the back seat and doing it, it is always great sex. But if we have sex in bed she is not aroused as much. So I eventually agreed to the back seat every time. The thing is , that when there is anybody in the area she will be looking over my shoulder as we are doing it and she goes wild if she sees anybody walking by, She becomes a tiger, no complaints from me at all. So anyway I bought a custom van as time went by and she has full control where we park when its time for her to turn into a tiger, her favorite spot is in a shopping mall parking lot where it is busy all the time. sex is very good for me unless I mention the bed.