Please I need some advice!

Last night after having sex with my boyfriend I asked him to tell me about his first time (my first time was with him so I wanted to know more about his and he always avoided this topic). When I asked him, he said: "Will you still love me or will you change your mind about me?". I said: "Of course I'll still love you.. but.. tell me.. what happened?". He told me his first time was with a prostitute last year (we didn't know each other yet). Now I can't stop thinking about him having sex with a prostitute. What should I do? I'm not saying I don't love him, of course I do with all my heart but I have these images in my mind and it feels strange.