Slutty Past?

Nicole • 26 years old | Ashton 3.15.17 💙 | Kiara 3.7.18 💖
Ok this is to be taken seriously obviously. I've been with my boyfriend a year and a half now and we are expecting our first baby! We are so excited and can't wait to be parents. Well, like every couple, we have issues here and there. Long story short, I was cheated on by my high school sweetheart as soon as I went to college and after we broke up I became a reckless little b*tch to say the least. I was into drinking, smoking hookah, and partying A LOT. I also had casual sex a lot as I was so anti-relationship at the time. Well, now being in LOVE with my current partner, it was only fair he know the truth about my past. He was really shocked when I told him and it causes him to occasionally worry if I'll ever do those things again. I can honestly say, all that stuff happened when I was around 18-20 years old and I have grown so much since then. I was what some would deem to be a "slut" but I was just living life carefree and didn't care about anything because I was so hurt by what my ex did to me. So my question to you is this: should I still feel guilty about my past? What can I say to him that will help him understand I'm not that anymore? I know we all have a past but I just feel so ashamed of how bad it got while I was in my college years.