A cognitive-behavioral therapist can help you develop a plan to feel better, not only by working through your feelings, but also by creating steps of mental and physical exercises to systematically lessen your anxiety.
But it doesn’t mean indefinitely or without boundaries. There should be a clear deadline (for his own good) as to how long he’s going to stay before enacting Plan B. And Plan B needs to be clear as well, whether it’s crashing with someone else, lowering his apartment standards or at least paying you rent. Your fiance should do this negotiating while you focus on starting your relationship with your brother-in-law on the right foot.
Andrea Bonior is a psychologist and author of “The Friendship Fix.” www.drandreabonior.com