Is he turned off by period sex?

My boyfriend and I had sex yesterday. My period typically lasts 4 days and it was supposed to be over by yesterday, I even woke up that morning with a dry pad and assumed that I was good to go. After we got going he pulled out and we both noticed that he was drenched in my blood, he said it was okay and we tried continue but it just wasn't working out. So we stopped to go shower and then we slept. Was he turned off by the sight of blood? Is sex on your period a good idea?