A tad bit sad

So I was in a relationship for about a year and 7 months and last nigh I was dumped. He now acts kinda gay I'm not being mean about him, he's a good guy, but he also was acting suspicious about one of his "exs" texting him and he got all defensive about it when I ask what her name was and what she wanted and also when his friend was joking around saying that he was cheating.
I honestly don't know how to handle this and I have to see him after school tomorrow. That should be interesting.