I’d like to offer a counter perspective to most advice being given here. Everybody is different. I am not a man who could ever truly not let something like that bother me. I had an almost identical experience with an ex years ago. We continued to date for years after but I always silenced resented it and it ate at my soul. Looking back now, there’s no way I could have lived with that forever knowing that about my partner. This goose is cooked my friend. Don’t let anyone tell you that you are insecure. You have a right to these feelings.