Do you think I should worry?

Okay, let's start off with this, im bi. And my boyfriend thinks it's awesome. He encourages me to find girls to play with. Lately, I've been talking to one of his old friends from high school. She's really attractive and he thinks so too. I told him we could have a threesome if we could talk her into it. And so we've both been trying. Yesterday however, she sent him a snapchat that I feel like he shouldn't have gotten and I'm worried that he sent more than he should have. Do you think I'm over reacting since I basically gave him permission to try and Persue her or do you think it should go through me to be safe?