Does my engine need a new head gasket?

At first, I noticed a small amount of water underneath the radiator area. Then drove it an hour away to work. On my way the radiator light came on and went off, came on and so forth. I had a mechanic who frequently works at my job put more antifreeze in it. It drove home great! But still had a leak. My boyfriend told me that I need a new head gasket, because quote, "I got it way too hot, and blew the head gasket!” He then took my “new” car and parked it at his friends. He bugs me to get a new head constantly! The car runs great, there is no white smoke, or water out the tail pipe. And last time I drove it, the water was all between the back of grill and radiator. I was also told that before a BMW gets too hot, it will shut itself down. Please help with my diagnosis.