Lose Control during make out

Hi, I am having this experience with someone I am seeing since couple of month.
The first time we were getting into it, I failed, couldn’t manage to get an erection. I explained that I was anxious, she came back and things worked, even though I wasn’t impressed about my performance. On that occasion she mentioned that for her sexual chemistry was very important.
Since then, we have had good times, however lately she is been telling me that I don’t lose control; I can’t seem to lose control according to her and that seems to be kind of an issue, as she would like very much me to relax. Now, I think I am relaxed, perhaps I am very worried about to performance and I have to say that my erection is seldom very strong. But I have started questioning myself. Do you have any suggestion?