My boyfriend, who has known me for a month, asked me to pay the accommodation and travel expenses.

I think AA system is better. If a man who has just known you for a month wants to be serious with you, he will care about his image in front of you and won't ask you to treat him immediately. From a man's point of view, I think he is playing with you. Because you just met him, you shouldn't ask him to pay. Since he said he had paid, it was unnecessary and unqualified. It's boring to be melodramatic. Let him treat you. Don't forget to buy him a gift of similar value afterwards. Just don't take advantage of it. If you share it in the future, no one owes anyone ~