This is a 2.5 Star. From a writing perspective, Ms. Kasari does a good job. Her writing is cohesive and it is obviously she edits and creates a nicely polished story. This makes it easier to read which is why I would give it a 3 star.
The sexy parts themselves are a bit staid. It's not that they are dull, it's a bit too tame for me. The concept of this story with voyeuristic fun and cheating in a swinging way is decent. More sexy time and less talking would be nice.
There is one thing in this story that threw me. 8 sexual partners is a lot? Hmm. I thought anyone with less than two digits in sexual partners is sheltered. I guess everyone has a different baseline.