What should I do when we see each other?
I am so sorry that this happened. Nobody deserves to be outed without their permission. I would encourage you to get in touch with someone who is supportive and accepting and plan to touch base with them after you see your wife's sister. You can also plan to take some time for self care after you see her. For example, if you enjoy bike rides, plan on taking a bike ride afterward. Plan to do something that feels nurturing and caring. Best of luck!