Great question. I wouldn't have believed it until I lived with it. Yes, it has cycles. Yes, it does affect brain chemistry. Yes, there are real withdrawal symptoms. I came to recognize all of these aspects of the disease.
Here are more references for you:
Brain activity in sex addiction mirrors that of drug addiction in ScienceDaily - https://www.sciencedaily.com/releases/2014/07/140711153327.htm
What is Sex Addiction? in Addiction Center - https://www.addictioncenter.com/drugs/sex-addiction/
The Six Types of Sex Addicts in Sex Addiction - https://sexaddict.com/six-types-of-sex-addicts/
I thought it was a convenient excuse, but I'm a believer now.
Interestingly, the WHO included it as a diagnositic category in the ICD-11
APA is slow to follow--I don't know why.
Hope this helps.