It Wasn't Just About the Sex Anymore

So here's my dilemma. I'm thirty-five and have been married for twelve years. After two kids came along, I didn't have much of a sex life until the past year when things with my wife started to heat up again, but then she went off on a work trip that unexpectedly extended due to some business crisis. We weren’t planning anything sexual while she was away because we were both busy, and it just wasn’t something either of us broached. Anyway, I've been seeing someone casually for the last month or so when my wife's out of town. Not exclusive at all, we had sex once a week when they fit into our respective schedules. And every single time was incredible, mind-blowingly good in fact. I know it sounds cliché to say something was the best you've ever experienced, but there were nights where I thought about how I should get her number before my wife left, just because. Now here's the crux of the problem: She texted me earlier today asking if we could do this weekend, she’s a nurse and off for two days. Thing is, it’s Friday evening and my wife got home from her trip way earlier than expected, like, right before the train pulled in at the station kind of early. So now I’m faced with the choice: either tell the nurse we can’t meet up because my wife's back (which I don't want to do, and she'd be really disappointed), or fib that everything's good on our end but not have sex with her when she comes over. Or the third option, which I haven’t seriously considered yet, is that I could lie and say something’s going on and get a last-minute hotel room. But honestly, even as much fun as it was with the nurse, there's this nagging guilt about potentially lying to both women. Plus my wife wouldn't know anything had happened, she wouldn’t think twice if we stayed home alone or went out together like usual, so I feel like the stakes are lower with her. Anyway, I guess what I'm trying to ask is: how do you navigate something that isn’t exactly a lie but also not entirely truthful? And at this point, it’s less about just having sex and more about maintaining a friendship with someone. But man, those orgasms were the best part of my week.