Boyfriends number

I’ve only been with my boyfriend for two months now but we were dating since June last year. We kept things quiet at first as we work together, he’s 26 and I’m 22. I haven’t been this happy in a long time, we are great together!

I found out on Saturday that’s he slept with over 40 people and it’s made me feel weird about sleeping with him now! What do I do?!