I'm sorry you are in this spot. As WalkinOnEggShelz said, the best you can do in this situation is to be as transparent as possible and as empathetic as possible.
Situations like this are an unfortunate consequence of our actions. When you poke an eye out, you have to live with the fact that it will be hard to see from now on. If you have an affair, you have to live with the fact that it has the power to hurt both you and your spouse at pretty much any given time.
My advice here would be to continue to focus on the "bigger picture", which is to continue working on yourself and your marriage. What your spouse needs to see is consistency over time, and to see positive changes in you over time.
The problem here (in my opinion) isn't your AP or what happened at the airport. The problem is that your BH still doesn't feel safe around you. He isn't sure if he can trust or believe you. All BS's know that transparency is kind of useless. If you really want to talk to your AP, you will find a way. So the question really becomes one of, "How can I restore trust?". And the high-level answer to that question is, "By becoming someone safer".
Every BS, at some point during R, asks themselves, "What about my spouse is different today than it was during the affair?". If the answer to that is, "nothing", then they are in the same place, with the same risks. I think what we (WS's) sometimes forget is that all of this transparency, timelines, NC and so on... these things don't indicate "change" of any kind. For example, if a drunk driver hits a car and then pays for all the damages, it doesn't mean he's not a drunk driver anymore. Paying for the damages is one thing. But he remains unsafe because he still drinks. In a similar way, all these things we do to "help" our spouses, are not necessarily indicative of change within ourselves.
Keep working on yourself. Ask yourself, your spouse, and your IC and MC, how you can go about being a safer person? If we stick with the drunk driver example, what if he were to join AA and get clean? What if he took medication that would make him sick if he took a drink? Better yet, what if he saw an IC and found out what factors in his life were causing him to drink in the first place? Ask yourself what would make the most difference to you? If he paid for the damages? Or if he turned his whole life around and removed the trauma and pain that caused him to drink in the first place?
Days and situations like this one will largely decrease when you become someone who has removed the core issue that lead to infidelity in the first place.