Hello Friend, Good that you are reaching this forum for help. From your short brief and background, it clearly shows that both are in good love and he is not doing any thing wrong without your knowledge now. If he had given all the password and details, it means he is not cheating you. Yes,Probably its embarrassing to know his past..but what's important is to know how is his behavior now. If you are satisfied, ignore this and move on. But if its still bothering you, better to talk to him directly and resolve it between both of you.
Health Tips
You may seek a help of counseling Psychologist if you are still not able to overcome.