Should I ...

So my boyfriend and have been together for 6 years and in 2 months he is moving in with me ... the past few weeks he has been hiding and lying to me . He has this one friend that cut him out of her life and now 3 years later she wants to be friends with him again. He asked me if I would be mad if he hung out with her I said yes I do not like her. And well he has been trying really hard to hid it and has been deleting messages . But he slipped up I know she has been to his house twice .. he has not told me about seeing her , or texting her . When I found out I wanted to throw up and punch him in the face . I am so hurt . I do not hide things from him at all . I just don’t kno what to do . I feel lik I need to have my mind made up before I confront him about hiding and lying to me ..