AITAH for not wanting my boyfriend to give money to his ex wife?

I (55 F) have been together with him (52 M) for a year and I love him dearly. The only argument we have ever had is about this. When we were driving to his home in Philly for XMAS (my 1st time meeting most of his family) I asked him if he had heard from her. I had looked at his phone once before bc something about their relationship bothers me. I found out that they still share a bank account and she had put him a couple of thousand dollars in the whole buy Coachella tickets. He was rightfully angry and she basically told him to get over it. I told him that I looked and that it really bothered me. I told him that they didn't have any kids and that there is no reason for them to share an account! I also asked him to close the account and to promise me he wouldn't give her money anymore money. She lives all the way in California so I really don't see any reason for them to talk at all. So when we were driving and I asked him about her he said no he hadn't talked to her. He then immediately said I'm lying and I don't ever want to do that to you. She called two days ago and asked to borrow $900 dollars. I was very upset. He says one reason I love him is that he is a generous person and she is his friend. Later that night I looked at his phone again and after he agreed to the $900 she immediately asked for $500 more. She wanted to buy her family nice Christmas gifts apparently and he gave it all to her. So he had indeed lied to me again. He doesn't know that I know about that. He told me that giving her the money did not effect our lives at all and that he will always help his friends. He also has not closed the account because he says he's lazy. Since then he said she paid him back but I don't know if I believe it. I have looked at his phone again and he is erasing their texts. We are supposed to move to PA this summer and I don't want to move with this woman in the picture. She treated him horribly for years and now I am in my eyes in her shadow. He doesn't even want to get married again because of her.