Confused

So me and my boyfriend have been working togther for years hes a handyman so he sees alot of people, i dont always go with him, so anyways theres this one lady that always likes to talk to him and so the other day i found out that they been calling eachother and just a few weeks ago he sold her some weed.I told him what was up with that and he said he wasnt going go stop. Should i be thinking negative over this situation ?