How Can I Check if My Phone is Being Mirrored?

Phone mirroring sounds serious, but true mirroring is more likely something from movies than reality. Since you mentioned your phone works fine after switching it to your ex, it could just be that your old phone had some issues. But just to be safe, make sure your accounts are secure and look out for any unfamiliar apps. If anything odd pops up, it's time to investigate further.

To help you better, we really need to know what kind of phone you have—brand and operating system. Some phones genuinely support dual SIMs, especially if you're traveling. As for 'mirroring', I suggest checking for remote access instead. Look through your apps for anything unusual or that you don’t recognize. If you're really worried about it and can't get to a store, maybe ask your carrier if they could help diagnose the issue over the phone.

I get that you're in a tough spot without local tech support. If you can, try to reset your phone to factory settings; this will give you a fresh start and clear out any possible unwanted access. Just make sure to back up your data first! Also, if you can manage it, look into some online tech forums or guides related to your specific phone model—they might help you spot if something's off.