I don't view "sex with others turns you on" and "madly in love" as mutually exclusive. Obviously you don't either, or you wouldn't be here I just saw the "but" and thought "hmm, no, I'm even more madly in love with her because I enjoy her having sex with others"...not a "but"
The conversation started with my wife and I after some years into our marriage when she commented one evening that she could imagine having two men massaging her at once (she looooves massage). That was sort of the snowflake that started the snowball that started the avalanche. Before I met her, I'd briefly been part of a poly triad. When my (now) wife discussed our past relationships and found out about this, she said there was nooooo way she would ever want to do anything like that. So, years later when she decided she really enjoyed having sex with other men, I was overjoyed and shocked. I'd learned too how much I enjoyed watching her have sex with other men. I've never been able to explain it, but I love it.
My wife has always been able to talk about things sexual. Her mother was always an open book, and my wife says she knows far more about her mother's (ample) sex life than any daughter ever. So, it's always been easy for her.
My wife and I already had an amazing, very open communication relationship prior to swinging. Swinging amplified that, but didn't increase it because we'd already had such open communication. For us, it was an exploration of things we'd never imagined. For my wife especially she found that having sex with two men in an MFM was something she really, really loves...something she never imagined.
I don't have any easy tips for how to get your wife to be able to communicate her sexual desires. It's a new mode for your wife, and trying to become comfortable with that may take time and lots of patience. Small questions like "does that feel good?" and "how does this feel?" may be the baby steps that slowly lead to deeper questions. Trust is important. Always be a receptive listener. Don't use sarcasm. Acknowledge. Support. Encourage.