My Girlfriend Doesn't Know I Slept With Over 60 Men.

I know this page isn't really meant for bi or gay guys, but if you could give me some advice, I'd really appreciate it.
I'm currently 20 years old, and I'm thinking about marrying an amazing woman. I believe that when you reach this point with someone, it's important to tell them your story—not only to avoid unexpected surprises, but also to make sure you're not hurting them because of things they don't know.
The difficult part is that my past involves dressing as a girl for men, sometimes for money, sometimes because of depression, and sometimes simply because I had extremely low self-esteem. I consider myself a femboy, and she knows that. I used to genuinely believe I was ugly, but she helped me realize that I'm not.
Looking back, I slept with a lot of men, mostly because I was desperate for validation. I could easily say there were more than 60. I want to be honest with her. I want to tell her everything and explain how all of this makes me feel today.
There were other things that came with those years of excess. She actually met me when I was practically in Alcoholics Anonymous. I regret that period of my life deeply. Something that still makes me feel ashamed is that I still enjoy anal sex, even though I know I probably shouldn't feel guilty about that.
I want to tell her all of this before I ask her to marry me, so that whatever decision we make is based on complete honesty. But the thought of losing her terrifies me just as much.
She was 19 and I was 15 when we first met, but we didn't actually become close until I turned 18.

Sorry if this sounds like it was translated or written by AI. I don't speak English at all, so I had to use a translator to write this.