Do you think it's ok that my fwb slept w/someone else?

We haven't seen each other in 3 months. It's been hard with the way our schedules are. He asked me if I had replaced him and I said no. I asked him if he has replaced me and he said no....but he said about a month ago he slept with someone. He said she turned out to be weird and he didn't even finish(he told her he was too drunk) and that he used a condom. He then asked me again later if I had slept w/someone else & said he wouldn't be mad if i had b/c he knows people have 'needs'. I told him that's a difference between him & I. I know that when you're fwb you aren't committed, etc. He was like....'i waited 2 months, almost 3.' WOW....what a long time! Am I wrong to be kinda appalled by this? He's my first fwb. I thought that if you were fwb you should limit yourself to just one....otherwise it's just sleeping around. I think it's nice that he told me....now I can make sure that IF I ever do sleep with him again I can be just that much more careful than I already am.