Erotica author looking for help.

Hi everyone.

I write erotica and I have a story I'm working on that I'd like some help on. Fair warning, infidelity is a heavy theme so if that's not your thing please stop reading.

So some background;

I have a story about a married woman who cheats on her husband with a friend of her husband's who is in the military and home from deployment.

I want it to be a short story. The first chapter is them having sex the first time in a spare room at the wife and husband's house after they run into each other on a night out.

The 2nd chapter is just after them finishing, the husband arrives and his friend goes to talk to him and say hi (husband didn't know his friend was back or at his house and the friend makes something up to explain this). The friend then excuses himself and goes back to the spare room where he has sex with the wife again with the husband close by so trying to stay quiet.

The following chapters will be them continuing an affair. The friend will always pull out without wearing a condom and will cum in various places while they have sex in wildly different positions than the wife usually does with her husband (drawing contrast between the husband's and friends physiques) until eventually the wife asks him not to pull out.

The issue I have;

I don't know how to tie this story off at the end. I want an ending that is conclusive, so the story is clearly over but also leaves the reader assuming something that might happen and maybe even leaving the story open to a sequel but not outright requiring one if that makes sense.

I'd love to hear any ideas you've got. Thanks in advance.