AITAH for not being comfortable with my husband sharing a room alone with a woman

AITAH for not being ok with my husband sharing a room with another woman? My husband S (23M) and I (26F) are arguing, and I could use an outside perspective. S thinks that it's perfectly normal to share a room (not bed) one on one with another woman because he trusts himself that nothing inappropriate will happen between them, and because he wants to split costs for a hotel room.

I am uncomfortable with him doing that. I trust him, but I don't necessarily trust the other person because I don't know them, and I think it's disrespectful to the relationship for him to insist on sharing a room.

His hotel room would be free, and she can afford the cost of a hotel room, or I suggested they split the cost, but he thinks it's just a waste of money.

As far as I'm aware, this is a pretty normal boundary for monogamous relationships, but he doesn't think it is, so I'm genuinely curious now. Is this a normal boundary or am I being controlling?

Edit to add: he has a work trip to her home state, and they are both close friends. They used to be FWB years ago, but have never dated, and they are NOT coworkers. It's not that I think he'll cheat on me with her, and I've never gotten bad vibes from her texts with him, and she likes a lot of our cutesy couple posts and congratulated us when we got married. I just want him to respect my boundaries and feelings, and I've never met her, so I don't know the kind of person she is aside from seeing her texts to him and her socials.

Editing again to add: This isn't a situation that's for sure going to happen, but there is a chance he will be sent on a work trip to the state where she lives and he used to live. Part of the reason he is bothered by my boundary is because he wouldn't have an issue if the situation were reversed, and I wanted to share a room with my best friend who is male. He's a lot more relaxed about stuff like that than I am, and he's a firm believer of "give someone as much rope as you want. If they choose to h@ng themselves or not is their choice, and it just shows the kind of person they are. He's confident in his ability to avoid sketchy situations and wouldn't be coming back to the hotel room drunk. Also, he's very open with his phone, and I've seen their text conversations multiple times (including deleted messages and all the socials they have each other on) and haven't seen anything at all concerning. We both have friends of the opposite gender who we've slept with previously, it's just this specific issue we're clashing over.

Also, we share finances, so it's both of us paying for it if that's what we end up doing

Editing again to add: she lives 2 hours away from where is work trip is, and they see each other less than once a year. Going to meet her halfway isn't really an option for him because he has to stay close to his work.