How wrong is it to tie up and tickle someone else's wife, if her husband doesn't know?
I have been trying to comfort myself by telling myself that I am not the one who is married, but does that really make it ok?
Sounds like a recipie for either getting shot or the beginning of a divorce.
The only thing stranger than the marriages of your neighbours is your own, and you know precisely 50% of the truth about that.
Two instances from my admittedly insane earlier days, relatively graphic so please stop reading if easily offended:
I'd gone to a fetish club in Birmingham, England with a girlfriend (kinky high school teacher- never had been tied and tickled before but loved it) in the late 1990s. After a bit of play with her and a few others I found myself with her and one other late thirtysomething woman, (neither was beautiful but both were happily willing) naked and kneeling before me, each nibbling up and down opposite sides of my 'Vaunting Enormity'. Pleasant enough, until I noticed a fellow watching out little threesome raptly, and I politely told him that we'd like to be alone. He turned angrily on his heel, left the little room, and things finished up nicely.
Afterwards, when the 'girls' were giggling and wiping their faces, I idly asked 'Who was that idiot?', and 'the other woman' replied, 'Oh, don't bother with him. That's my husband.'
Another time I'd met a fortysomething Yorkshire couple at another fetish club, this one in London, and his thing, with her enthusiastic acquiescence, was (every so often when my in-the-process-of -divorcing-me and definitely no longer sleeping with me previous wife was at work) to send his own wife south on a 150 mile train journey with a checklist of things he wanted done to her, including little drawings of what he'd like the marks on her bum to look like. She was pleasantly unremarkable in looks, had children, and he'd email pictures of her holding herself open for the camera. Unfortunately she wasn't particularly ticklish.
However, if this will amuse anyone, because my then-wife would always find fault with whatever housekeeping I attempted, on the four or five occasions 'Mary' was sent to me, I'd sit glaring sternly at her, have her strip, then aided by cane and flogger would have 'my naked slave girl' as she liked to consider herself clean the flat before more intimate duties were embarked upon.
And when Wife would return from work to see me (having timed things carefully, knowing when she'd get home) mopping the already sparkling kitchen floor in our now immaculate flat, she'd beam 'See how well you can clean if you really try?"
So, OP, I can't really advise you because every situation is different, but ask her careful questions and maybe at least for a while, things will work out.