how do I stop people I don't know from using my account on their Xbox?

Make sure the new password you set is considered to be a "strong" password. There's a wide range of articles that describe how to setup a strong password.

If you haven't already, I would recommend that you Setup two step authentication for your account. Not only is your account protected with a password (first line in defence), but also with a security code, unique for each new session, or trusted on a known
device for a certain timestamp.

Please read: https://support.microsoft.com/en-us/help/12408/microsoft-account-about-two-step-verification

You'll need to contact support and have them start an unauthorized access investigation. http://support.xbox.com/contact-us

For account security issues you should contact xbox chat support my account section: http://support.xbox.com/en-US/contact-us

or if you are part of the US/CA region contact (800) 469-9269

I have a ex husband and he has Xbox. Ii was openi.ng up my settings and I saw that there is a device recording audio and mouse movement I dug deeper and found than Xbox attached to my Microsoft account and it's been recording my audio how do I stop that
and how do I make sure that he gets in trouble for doing this I don't know how long he's been doing but I know he does it all the time I know this is not the first time I know that he is been continuously hacking my account changing password just basically
non stop harassment and this is the final straw... If you can tell me how to disable the Xbox account with at least how to appreciate it

.

Hell Snqkee,

The parent/guardian who setup parental controls will need to sign to adjust any parental settings.

They can do so at https://family.microsoft.com

Best regards!