My controlling boyfriend set a SCREENTIME passcode under his I cloud what do I do

Are you signed in using your Apple ID, except for the Screen Time passcode?

You can try doing the below as a first step, but it may not work.

Screen Time passcode reset

If the above doesn't work, you will need to restore the device to factory settings. Do not restore from a backup made when the Screen Time code was active.

Restore to Factory setting.      

A computer would be the best way to do a reset. Are you signed in using your Apple ID? If not, see the post above about removing the Activation Lock.

If your device is under another Apple ID, all of your Messages comms can be monitored, and all of your movements can be tracked with Find My, and your passwords can be known, among other details.

With the Activation Lock reset, you’ll then be able to clear Screen Time.

The only way to remove Activation Lock for a case such as this is with the password (and a password that you likely don’t have), or with the original purchase receipt and matching ID and a discussion directly with Apple.

If you chose the path to schism, you will likely reset your devices (or potentially replace those you can’t salvage), and will absolutely need to change all of your passwords particularly your Apple ID, and the passwords on your email related to your Apple ID reset path as well as your related account recovery information, and your social-media account recovery paths, and change your device passcode.

Your options here are not good. Contact the local police if that’s an option for you and where you are, or leave. From many years in emergency services, similar situations only tend to escalate. (And I’ve encountered cases and outcomes I’d rather not describe here.) If nothing else, have a chat with trusted friends and with the local victim’s advocates folks, too. The advocates should have more and better suggestions here than I might offer here, too.