I like to think about my boyfriend fu*&ing his exs

okay so my boyfriend admitted to me that he lied to me about how many girls he has slept with... and then he went into detail about all of them. most girls would get jealous if this happend to them, but i just kept wanting him to tell me more. the more he told me in better detail the more turned on by him i get! i love thinking about him f@#cking other girls. ever since we talked about it i cant stop thinking about wat was said. i love that im so turned on by it but i dont know if i should be this okay with knowing things in such detail... our sex life was starting to dwindle but now that we have had this convo i desire him so much more.... anyone know why? is this normal?