See man

How much total semen does a man produces in his lifetime?

Average ejaculation: roughly 3 milliliters. Average frequency: about twice a week  Lifespan of sexual activity: say 50 years.

So: 3 mL × 2 times/week × 52 weeks × 50 years = 15,600 mL.

That’s about 15.6 liters. Around the volume of a standard kitchen bucket.