Cheating in a relationship :(

Okay, so 2 years ago I cheated on my SO, he took me back. He was my first love and I was his.. We both lost our virginity to each other. Yes he has his ways but he is the best thing that happened to me, I actually prayed to God for this man. We been together going on 6 years. But I guess I was more curious than anything I gave it up to a 40 year old I work with :( and I work nights.. TMI but the only reason i did it is bc I never received oral sex. And i wanted to fit in...I swear it wasn't worth it!....still til this day this whole situation feels fresh to the both of us and I tear up about it all the time and get frustrated at the fact that I did it and how I destroyed him!! I feel so EASY, STUPID, and WORTHLESS...but he still loves me it hurts me to know I hurt my first love like this...the love of my life. And now I want to get married B/C I feel like my blessings are getting blocked from pre-marital sex...and i keep asking him when are we getting married..but he said it's not easy for him and I understand he just can't trust me right now...he always try to sneak up on me to see if I have anyone in the house, or he is always accusing me of doing something. I've totally learned my lesson and I it won't happen again....I believe that time heals all wounds....and I know that God is a Healer and Forgiver...everytime I think about it I begin to say Lord forgive me bc I just feel like I can never be forgiven for that.. I've never smoke nor drink I'm a good girl so that was pretty much the worst i ever done in life 😞...  Am I wrong for wanting to get married?...is it too soon? How long will this take to heal?  

If anyone has been in a similar situation please feel free to talk.. And also please don't judge me :(  or if you have any suggestions...anything.