My Dad is soliciting sex workers

I was on the family computer looking for the password to my Minecraft account which is registered under my dad’s Microsoft account as it was made when I was a child. I couldn’t find the password however, what I did find was my dad’s log in details to a site called “Adult Work”. Upon further investigation into the site you can solicit cam girls but also escorts on this site. I’m unable to tell what services my father is paying for however after discovering the ‘feed back’ section on his account it is obvious he has been paying for services.

My father works away for most of the year as his job requires him to travel frequently.

I’m unsure what to do. My parents are still together and I’m aware that telling my mum this information will greatly upset her. My father is the main earner in the household and supports the entire family financially. Should I speak to my Mother or Father? Or should I keep it as a secret and pretend i never found it out.