I'm going to name what's happening here, even though I know it can be a stressful word to describe oneself with -- jealousy. But guess what -- jealousy is natural and okay in and of itself! It can be easy to experience this emotion in a relationship that is precious to you and that you're protective of, especially if your partner has more sexual and/or dating experience than you do. I get it.
That being said, jealousy isn't a bad thing, but we have to be responsible for how we respond to feelings of jealousy and insecurity. It's important to remember that this person is choosing to be with you right now, and that that speaks to their care for and prioritization of you. It's also important to remember that our partners don't need to feel ashamed of their past, even as we navigate our emotions around that past tenderly. I love this quote from our article, Jealousy: Making Friends with a Green-eyed Monster
It requires patience, love and kindness: to others but, most importantly, towards yourself.
So, I recommend you start by loving on yourself and soothing those insecurities! Set boundaries around what you and your partner talk about together (it looks like you're already doing this, which is great!) and make sure you're both
comfortable with those boundaries. Take space and/or ask for some extra time and validation as needed. Practice self-care. It'll get easier to let go of these feelings with time.
Let us know what you think of that article! I'm curious to see if it helps. Please note that it's written by a polyamorous author -- but feelings of jealousy are universal, and it should still be helpful in your situation <3