I disagree. I think CM had a lot of built up resentment and jealousy towards Joey and Summer. He even said snarky things about the boys. In one interview he mentions that Summer 'didn't believe in corporal punishment.'
Why would a 2 and 4 yr old require any form of corporal punishment?
Joey was renovating a beautiful new home that he just bought for his family. Joey had plenty of money in the bank, a bright future with millions in upcoming fountain contracts about to roll in. And many people loved and respected him.
Chase was in the exact opposite position. He was living a nightmare. He owed thousands in tax liens, law suits, gambling debts and overdue bills---his rent was past due, he lost his checking account because of all the overdrawn checks, he had no credit, his health was failing, and just when all these huge contracts were about to pay off, Joey began farming out the work to another company.
He had young children, like Joey did, but the mother of his young children did not even give them Chase's last name. They depended upon him but he constantly let them down, by getting arrested, or gambling away his payroll checks etc. Their life was erratic and chaotic compared the Joey's kids.
Joey was 'his best friend' and 'his business partner' ---but that was only in Chase's warped mind. Joey treated him very well and enabled him, but they were not 'equals.' And Chase knew that.
I think the stress and resentment built up ---gambling addicts live a holy hell---scrambling to feed their ugly greed and lying and cheating and stealing from friends, foes and strangers. I think it all came to a head because Joey had finally had enough.
JMO
ETA:
This bit of testimony, from an officer conducting that Feb.17 interview of Merritt:
Q In fact, didn’t he say there on the 17th that Joseph was
one of his best friends?
A Yes.
Q Didn’t he say that Joseph definitely loved Summer?
A Yes.
Q And didn’t he say she was a verbal person — was a verbal
person?
A Yes.
Q And she didn’t believe in corporal punishment?
A Yes.