Objective Studies indicate that social constraints (barriers to emotional expression) may be a risk factor for psychological morbidity. We aimed to investigate the association between prostate cancer‐ related social constraints and psychological well‐being following prostate cancer surgery. Methods In a group of 3478 partnered patients, participating in the Laparoscopic Prostatectomy Robot Open (LAPPRO) trial, a prospective multicenter comparative study of robot‐assisted laparoscopic and retropubic radical prostatectomy for prostate cancer, we used log‐binomial regression analysis to investigate the links between prostate cancer‐related social constraints at 3 months after surgery and psychological well‐being at 12 and 24 months. Results 1086 and 1093 men reported low well‐being at 12 and 24 months, respectively. Prostate cancer‐related social constraints by partner predicted low psychological well‐being at 12 months (adjusted RR: 1.4; 95% CI, 1.1‐1.9) and by others (adjusted RR: 1.9; 95% CI, 1.1‐3.5). Intrusive thoughts mediated the association. Conclusions Negative responses from the social environment, especially from partner to talking about the prostate cancer experience affected patients' psychological well‐being two years after radical prostatectomy. Results emphasize the importance of helping patients mobilize psychosocial resources within their social network, especially among those with a lack of quality psychosocial support.