Here is my advice: Closure is always good, so sending an email (not a text), is a good idea. With that said, your immediate reaction was understandable, particularly when the news was unexpected and delivered in a public venue and in a very impersonal way. Interestingly enough, guys often think the way to let someone down is over dinner. Perhaps, that seems easiest and best for them, but it's a horrible experience for the receiver. It is, quite frankly, in poor taste. So, I think it is fine for you to write a nice email, explaining that you are truly sorry for your physical reaction to the way in which he chose to announce he was ending your relationship, but that had he been in your situation, he might have acted similarly. Thank him for the good times you have shared over the past six months, wish him well and educate him that for future, when he is wanting to exit a relationship to give the other party the courtesy and respect of doing it in a private place where there can be civil conversation and both persons can part with a better understanding of all of the pros and cons about the relationship, so your next relationships will be better for each of you.
Forgive and move on with three things in mind:
1) Be prepared to go into the next relationship when you feel strong and happy with yourself
2) Watch for red flags early when dating, so they can be addressed.
3) Vet your partner thoroughly for lifestyle similarities, interests, passions and pay close attention to how they treat you and others with whom they come across as your relationship is progressing.
Do you have a question about your relationship? Need some advice?
I would be more than happy to offer guidance. Feel free to email me or post a private message on my Facebook Page.