"What do I get out of it?"

Not to get too into how we got to this point (search my posts if you like), but my wife (early 40s) and I (later 40s) are considering opening. After a start fraught with miscommunication on both ends, my wife has spent some time reading and listening to things to try to understand why it interests me as much as it does.

That is, she understands that I am more outgoing and love meeting people, have a somewhat voracious libido (our sex is regular in frequency and terrific, but I can pretty much always go for more), and am really into experiences. But she doesn't quite understand why, if I'm attracted to her (which I very much am), I love her (which I very much do), and enjoy our sex (which I also very much do), how is there still a desire within me?

For my part, I'm not sure how I'd define what I'm looking for. I'm open to one-time hookups, but I also went on an initial date with someone I really liked and saw as a potential long-term thing.

My wife, for her part, doesn't have any desire to date (she's hot and would do just fine, but there are a number of reasons she has no desire), but she has expressed openness to a FMF threesome and talked about hooking up with a couple.

If I were to date though, and she never bothers to try it herself, she wondered what would be the benefit for her. She read up on compersion and isn't sure she'd be able to feel it.

I've read enough to know that I should in no way pressure her into agreeing to something that she is uncomfortable with, and I'm letting her drive the conversation, only really discussing it at this point when she brings it up. As I said, she's not totally opposed right now, but I haven't been able to answer for her what she gets out of it. Telling her how appreciative I'd be of her letting me do this, or how I feel like it would just lighten me in general, feels like kind of a hollow thing to tell her.

So I'd love to hear from anyone whose partner is dating while they choose not to. Why are you okay with it? What do you get out of it?