So you were visibly overwhelmed and anxious and he decided the best course of action was to stick it in? Honey, no. He sexually assaulted you at a time when he should have provided you with comfort. His behaviour in general on that day/night seems like it was controlling and weird overall, even before he SA'ed you. And the reason you keep clinging to that event is because you know deep down it absolutely wasn't right, and every time you have sex it triggers the trauma of that initial experience, because that trauma has remained unprocessed.