PLEASE HELP!!! I dont know what to do!?

I lost my virginity on accident when I was drunk and high { I regret it so badly} and me and my bf have been going out for 1 year and 3 months {we were apert when it happend} I am clean and have been good ever sence but I thought he already herd what happend.. Well we talked about us going all the way and what he said told me he had no idea... I dont know what to do.. do I tell him a risk it or not..I dont want to but what would be best???please tell me and dont judge me to harshly :(