You seem to be suffering from diffuse patterned hair loss (a type of androgenetic alopecia) and you would require treatment like minoxidil, finasteride, prp , laser and hair threads to treat the existing condition. Remember, with these or other non-surgical treatment, the progression of the disease like thinning and hair fall can be stopped and thickness of the hair can be restored to some extent which should be sufficient in your case. However, medical treatment do not regrow new roots.
regarding the side effect of minoxidil, it does not cause any sexual side effects as per present scientific knowledge. however, finasteride can cause it and therefore, your doctor has prescribed no oral medication.
Next Steps
i would advise you to consider prp therapy along with microneedling and hair threads to have faster and long lasting effect if thats what you are looking for