Thanks for your query.Based on the facts that you have posted it appears that you have undergone cryosurgery
enlargement 6 months back.
During any surgery for prostate the neck of the bladder is incised or resected.
In a normal situation during ejaculation bladder neck remains tightly closed which prevents the entry of semen in bladder and facilitates the passage of semen in urethra
However after surgery on prostate the neck of the bladder being resected this mechanism is lost and semen enters the bladder what is called as Retrograde ejaculation
This is the reason for no semen coming out through urethra,
As regards passing watery duischare per urethra it is an excessive secretion of peri urethral glands located in urethra and it gas no significance at all.