How to have a threesome without getting jealous?

So my boyfriend and I love each other more than anything and we’re very committed to one another. That’s clear on both sides. We’re also both pretty freaky in bed. Threesomes have been discussed and I’m pretty open to it because he said I can pick the girl and if I happen to change my mind, we won’t do it. No questions asked. The thought of hooking up with a girl while he’s watching is hot af to me because I know it’ll turn him on like crazy. I’m only bothered by the fact that he will be fucking her too. Like that’s MY dick. I know he loves me and he makes me feel like I’m the most beautiful girl in the world daily so idk why I’m acting like this. And no, I don’t consider a threesome as cheating.

If you’ve had threesomes, help a girl out lol