Hi Christian,
I'm sorry to read what happened between you and your bf.
When my bf gets jealous (or vice versa), I usually tell him I know he cares otherwise he would not have gotten jealous.
Lol. However, I know there's more to it.
In overcoming jealousy, firstly we have to learn to trust out partner. When they say something, we must let them see that we trust them, and believe them instead of doubting and getting angry.
Trust is important in all relationships. I think one of the reasons that caused the jealousy is because maybe you compared yourself to the girl your bf was talking to. You described her as
'a beautiful young blond'.
Please remember that you are beautiful too and your bf chose you to be his partner. Comparing yourself with her may have caused some jealousy to stir up. Try to stop comparing yourself. Please know that you are a wonderful person and remember that your bf picked you for his gf because of many good reasons.
If your bf brings back the topic again, explain that you were jealous hence why you did what you did. Let him know how sorry you are, and now that you have apologized you want to move forward with him. If he keeps bringing it up over and over, maybe you should just give him some space and don't entertain the topic. Eventually he should stop bring it up and move forward.
I hope things will settle down soon and go back to normal with you and your bf.
UA