One point is catecholamines (like dopamine) are present in human seminal plasma and might be loss by ejaculation. In the same time, lot of dopamine is released during orgasm. Which it make a "double" usage of dopamine.
The second point is the effect of dopamine depletion, showed by scientific study :
https://www.yourbrainonporn.com/relevant-research-and-articles-about-the-studies/dopamine-and-addiction/subjective-experiences-during-dopamine-depletion-2005/Mr. A was a healthy, extraverted, very well functioning 21-year-old medical student without even minor psychological difficulties or psychiatric disorders in his family. His Global Assessment of Functioning Scale score was 97. Written informed consent was obtained from Mr. A. We will describe the spontaneous reported subjective experiences after he started the first dose of 750 mg AMPT at t=0 hours (1).
After 7 hours, Mr. A felt more distance between himself and his environment. Stimuli had less impact; visual and audible stimuli were less sharp. He experienced a loss of motivation and tiredness. After 18 hours, he had difficulty waking up and increasing tiredness; environmental stimuli seemed dull. He had less fluency of speech. After 20 hours, he felt confused. He felt tense before his appointment and had an urge to check his watch in an obsessive way.
After 24 hours, Mr. A had inner restlessness, flight of ideas; his ideas seemed inflicted, and he could not remember them. He felt a loss of control over his ideas. After 28 hours, he felt ashamed, frightened, anxious, and depressed. He was afraid that the situation would continue. At that time, blepharospasm, mask face, and tremor were noted. After 30 hours, he was tired and slept 11 hours. After 42 hours, he had poor concentration. In the next hours, he returned to normal
Testosterone being dopamine-related, this might explain why some guys got Pois after 40+ years when testosterone starts to decrease.