Ho hum, 2.5 generously rounded up to 3. Easy going read with 3 guys navigating the logistics of a ménage relationship. It's kind of fun to see how it comes about. And it's kind of fun to see who they reveal themselves to as a "group". There were two plot points that I thought did not serve the book well, but made for some interesting thoughts.
Caleb, the junior partner in the group feels insecure because he has to go on an out of town work assignment. That seems reasonable, he doesn't quite know where he ranks in the group and what might happen while he is away. Since there was no discussion about the dos and don'ts of the group dynamic, he was understandably insecure about where things stood with the other two. After being away for a week, Caleb should have been comforted when Scott said:
"Caleb. We don't fuck when you aren't here. You really thought we would?"
Ah yeah, I would have. Here's the thing, there is no handbook for what to expect with polyamorous relationship. The group, in this case all 3, need to discuss what is ok and not ok. Communication is essential. But this group did not communicate any expectations. In what I thought was an ironic twist, Scott later clarified well, we do jack each other off when you are gone. Well, duh.
This leads me to the second plot point that left me squinting. Out of nowhere and based on nothing, Chris became the jealous possessive type. I will admit, that this trope occasionally
works. But usually there needs to be some reasoning behind it, even if that reasoning is points to something remote such childhood abandonment. In the strongest shape, Chris's possessiveness was not justified by the actions of his partners, nor was it explained in any other way.
In the end, the guys work out some of their issues and decide for them, the triangle is "the strongest shape". That is nice and poetic, but I am not sure the structural engineers would agree.