What is the ruling on masturbation before intercourse if it is the only means to delay ejaculation and complete the marital act?

Masturbation is forbidden and has many harms. It is not permissible to engage in it or to justify it. If you are able to approach your wife after masturbation, you can approach her a second time after the first ejaculation, thus fulfilling her needs without falling into the sin of masturbation.