I've contemplated it - recently. Slightly different situation to you, as it was a person known to both of us. He really flattered me and, similarly, I am lonely and susceptible. We got to a point where I got drunk and we exchanged some inappropriate texts. Then I woke up to myself. I would say that up to that point I felt like I was in a dream, I was consumed with thoughts of him and lived for the next tiny contact. I really craved the reassurance that I was still attractive and that he was prepared to go out on a limb for me, I saw it as a romantic gesture rather than a sleazy manipulation to get into my knickers.
It was at a point where we were going through a horrendous time in our marriage and I used to lie in bed next to my sleeping DH and silently weep about how unhappy I was.
What stopped me from actually having sex with him was endlessly reading the threads on here where the other person had found out and what it had done to them. I do love my DH and, although he is very difficult to live with at the moment, he is not a bad person and does not deserve to go through that devastation.
We are trying to make our marriage better, and I am (through counselling) trying to work out what brought me to that point.
If it helps to know, the day after the drunken texting, I felt sick to my stomach and so remorseful. I couldn't look my DH in the eye, I felt terrible and massively over compensated as a result. It wasn't worth the cheap thrill I got at the time.
I still worry that what happened will come to light, and it is not a comfortable place to be. The man involved is still a part of our social circle and it's very difficult to cut him out without a good reason for DH. That's my penance though.
I don't think a one night stand is worth it. You're not in love with him and you're not looking to leave. Either the sex will be a disappointment and you'll feel shit that you've betrayed your husband for that, or it will be great and you'll want more.
FWIW I am someone who had lots of one night stands when I was single. Some were amazing, some were damp squibs. The ones that were amazing inevitably left me feeling like there was a connection that I wanted to follow up. Sometimes it carried on, sometimes not. When they weren't interested after a fantastic night, I felt shit. If you add in a load of guilt you'll feel terrible.
I don't think you are a terrible person, and life is not as black and white as a lot of posters make out. But I think, like me, you are carried away with the fantasy at the moment, and when it becomes real it will be a disappointment. He won't live up to your dreams of what it will be like.