I had a laparoscopic inguinal hernia repair on the 8th of october. my question is when can i resume sexual activity (+ masturbation)?

Up to you: The good news is that none of the plumbing would have been disrupted in a typical hernia repair. Even if the vas deferens had to be cut free from adjoining structures it was stuck to with scar tissue , it should not have been cut. But the crotch is a major intersection of legs, body, and genitalia so the gymnastics of sex will tug hard at incision lines . After two weeks pain can be your guide.