Doesn't H's email sound very casual?? He decided that I am okay with him coming back to our house freely?

I do not want to sound like a controlling and cold b****, but I do want to make a point that I do not want S3 to be involved just yet. He is going to get his hopes up and get hurt.

How about if I reply to his email by saying:
"S3 has his class tonight (which is true - I told H about S3's class on Tuesday nights so many times before but obviously he does not remember) and we will be late, so it will not work for us. If we are going to have dinner, I do not think S3 should be present yet at this point".

How does this sound?