Hi,
Welcome to Health Care Magic,
I am Dr.Naveed Ullah khan,
I have read your question in detail and will try to help you in the best way possible.
Sperms not coming out and going back can be due to retro ejaculation. There are pathological processes causing this. For that i would like u to have a physical exam with your genwral practitioner. And if necessary do am imaging study to find out if there is any anatomic abnormality in ur
urethra and vas deffernce that is the duct which carries the sperm to the urethera.
About the leision on ur penis it definitly needs to be tested in order to rule ouy aby
sexually transmitted disease. As you mentioned you have been with the same partner for 20 yrs there is a posibility ur partner migjt have the infection and transfer it to you. Whatever the case might be, even if u and ur partner are monosexual, i still suggest ruling out
syphilis amd otger sexually transmitted diseases.
I hope this answered all your queries, if you have more queries,I will be happy to answer.
Wish you the best of health.
Regards.
Dr.Naveed Ullah Khan.
MBBS
USMLE step 1, 2 & 3.