Anal Sex

So...I don't usually let my husband have anal sex but I told him I would for his birthday. Well we did last night and it actually felt good (last time it killed) so I told him we could start doing it more often. So we did again tonight but this time in the middle of anal he saw blood and said I was bleeding.

Has this happened to anyone else?

I've never had it happen before and he is really worried something happened.