Sexual past.

Update: reposting this with a new title cause I didn’t use an appropriate one before

So I (mid 30’s female) need to get this off my chest and also would like to hear what ppl may think about this. I truly don’t know how many people I have been with sexually. My high school years I never was asked out or looked at and then in my 20’s I guess I got a bit “hotter” and I was getting attention from men. Not something I was ever used to. I didn’t sleep with every man who ever looked at me, but I didn’t really ever see an issue hooking up with a guy I wanted to hook up with. If I had to guess l’d say my number is maybe around 20 but I never wrote down their names or kept count. I don’t feel super embarrassed about it necessarily, but it’s definitely a secret I have held since no one has ever asked. Even my friends don’t know about every single one. My current partner and I have been together over 8 years and this has literally never come up nor have I been asked. I know my partner has a much lower number than me.. like wayy way lower. And at this point I don’t really know how to bring it up to him. If he asks I want to be honest but I truly worry that he will look at me different after that. I really hate myself for not just being honest about this a long time ago. But I’m here in this situation and truly do not know what to do.
Please don’t be too mean to me about this. Like I said I feel very guilty and stupid that I never just brought it up.