Is it normal for your boyfriend to ask his ex to send naked photos of herself to him?

We have been together for 6 months and are living together. I discovered naked, posed photos of my partner's ex on is computer that she had just emailed him. At first he denied it, then admitted that she offered to send some and he said that would be ok. I suspect he asked her to send them in the first place.
He said his only mistake was not deleting them and that it is perfectly ok to view pictures of this woman that he once loved.
He also emailed her thanking her for them and saying that he "used them" for his own pleasure, after promising to cease contact with her.
He is trying to tell me this is what any guy would do and that not many men would find this that wrong.
He says I'm over-reacting, is that true?