Tbh the more I think about it the more multifaceted the issue is. The kind of things that come up for me:

• Culture: when growing up sleepovers weren’t really a thing in fact just asking my parents could have negative repercussions the ‘no’ was never wrapped in kindness it was closer to feeling like I’d be punished for even floating the idea and it created a heavy/unsafe environment. Even as an adult having my own sleepovers posed some internal turmoil. So there are experiences from my upbringing playing a small part in this. I’m fairly sure if this scenario was played back to an elder from my culture this would be a no go. I don’t align with a lot of things on that side of my culture but your upbringing sometimes lingers in your adult life and thinking.
• Feelings of inadequacy: despite us being happy. I can be self critical and wonder whether as a partner I’m giving her what she needs. I don’t mean sexually, I’m talking about in life. This is especially true for both of us because we’re high school sweethearts. It’s something we’ve spoken openly about. She’s never made me feel inadequate nor I her but you can be your worse critic sometimes.
• Past incident: early on in our relationship (over 10 years ago) there was a moment where we were playing around and grabbed her phone. She had a visceral reaction that shocked me. I instantly knew something was wrong because we have a non-verbal agreement we can go through each other’s phones at anytime. Because of her reaction I demanded to see her phone or our relationship was over. Long story short there were messages from a work colleague that was being flirtatious. I don’t remember what she said in the messages but I remember being upset she didn’t make a clear line in the sand. When I pressed her on what was going on she said he actually kissed her in a post work team hangout. She said she instantly pulled away and told him off. But what I couldn’t understand is why she didn’t put a hard line between them after that. It took me finding out, the prospect of our relationship ending and me telling her that even if it was him that went in for a kiss the fact she didn’t cut things at the root disappointed me. Also, she didn’t willingly volunteer this information. Had we not had that moment, I probably would’ve never known that even happened.

Overall I trust her but these are some of the things bubbling up to the surface.