Ok, so you have Sebastian and Barbara, who find themselves neighbors to Mattie and Butch. Mattie notices Sebastian. Butch notices Barbara. Barbara notices Butch. Sebastian has his head up SOMEwhere and notices nothing. Butch and Barbara have a fling. Mattie finds out about it, confronts Butch who proceeds to plow his cessna into the side of a mountain. Sebastian pats her on the head and wanders off. Barbara files for divorce eventually and informs Sebastian of her fling. Sebastian is blindsided but says nothing.
2 years later...the book starts. At this point, Mattie has been widowed 5 years, Sebastian divorced a little over 2. He's decided to end his celibacy by inviting some chick at the bank over for dinner and benefits. Mattie is well aware of this because the chick has been boasting about it.
Enter Elizabeth, a baby, daughter of a girl Sebastian and his friends had been stranded during an avalanche with. Sebastian is convinced it's his even though the note the girl left him when she dropped the baby off on his porch gave no clue as to paternity.
I still have difficulty with the friends to lovers bit. In this case, the h has a crush and the H is oblivious. Hard to imagine a friend not picking up on that, when his buddy apparently did.
Eventually he comes to his senses but it was practically the last pages, and after the buddy had told him off.
As an aside, supposedly the dog had puppies 10 years prior, but then she didn't show up until 8 years prior so...