Is masturbation harmful to a guy and does it weaken erectile strength over time? my erection is weaker than it used to be so i stop mastubation.

See below : Masturbation is a very common and healthy normal behavior, even among people who have a sex partner. It is not physically harmful, though excessive, compulsive masturbation may have an adverse effect on quality of erection and/or ejaculation and, depending on one's upbringing and religious beliefs may cause some people psychological distress, guilt, and/or shame. It does not weaken one's erection.