Deliverance has a pretty good wife sharing path. There are several branches storywise, like if you want to cheat on your wife and romance somebody else, but if you stick to the sharing path it's pretty much exclusive and linear and no cheating/ntr is done (the wife never cheats anyway there is no pure ntr path)
Ruins of Luxoria is unique in that you start off single in the game then as you progress the Mc and love interest becomes a couple, then from there you can either go vanilla or choose the sharing route and have her sleep with other men. There's even an option to have someone else take her virginity on your first sex after being her gf, but she stays loyal to you no matter what.
Helping Out the Neighbor is pretty quick and linear kinetic novel. Just a quickie with the husband requesting his wife to help out their friendly neighbor and things escalate quickly.
Exciting Games is also one solely dedicated to hotwifing without any cheating, but the game likes to take the story slow so the corruption and agreeing of the wife to finally sleep with other guys is slow.
I played numerous other sharing/netorase games as well but they have a ntr/cheating path on them which you mentioned don't like so I won't share them, but if you are interested for other games like this regardless, feel free to hit me up.