Orgasm

Okay so me and my boyfriend have only been having sex for about a month but I had to move to college but I'll be back and moving in with him. When we have sex I either don't realize that I've cum or I just haven't. Idk how to tell. He says that I'll definetly tell but what if I don't? On the night of my graduation he was fingering me and it was very intense. I've never felt like that before and the only reason I knew that I had cum was because it was EVERYWHERE. Then he started again and I was kind of throbbing a lot, and I knew I was going to again. So I made him stop. Partly because it scared me and partly because it was very intense and I felt very overwhelmed, but it felt amazing. Since then it was about a month or so and we starts having sex but I've never got that feeling again. But I feel really satisfied and happy afterwards. So is it possible that I do cum and not know it or am I not doing it at all?