Should I reveal my finances to my Fiance even if he does not reveal his to me?

Sometimes I ask my fiance to pay for gas when we use my car to drive around time and go out on the weekends. So, I asked him very politely if he had cash on him because I needed to get some gas...He gave me the cash but he also stated to me that he wants to talk to me about my finances because if I can't afford gas, there must be a huge problem. I do not have problems with my finances, everything is paid on time every month.