My fiancee is upset after I told her my partner count. What should I do now to handle this situation?

Note: Sorry if my English isn't good, it's not my first language.

I have a great relationship with this woman and we're planning to marry soon. Earlier today, she asked me how many women I've been with. I didn't wanted to lie to her... so I admitted that I've had more than 10 partners.

She didn't react well. She got mad, she talked little, she didn't wanted to hold my hand, and then she left soon after. I never saw her this angry before but I still held my frame.

She's different. Unlike me, she never had sex and she's saving herself for marriage.

What was I supposed to say? Just dodge the question and joke about it? I did this twice already. Gaming and not letting your guard down around women is harder than I thought.

So... what am I supposed to do now? This is the biggest shit test I've had in my life. I honestly don't know what to do tomorrow when I see her. What should I tell her? The best I can come up with is "Would you rather I lied to you instead?" or "It was worth saying just to see the look on your face?"