Wife's photos in my photo app

Unless these photos are showing just in shared albums (Eg the shared family album) then the only way this can happen is if the same apple ID is put into the devices that are sharing a library. I suggest you double check the id in your new macbook, and her phone.

One other possibility - if you are sharing the macbook pro library on an external drive with your and her accounts on the mac both accessing it - this will do it also.

where are your wife’s photos appearing in your library? you may now be seeing all phogos shared to you in Messages in your Photos Library, depending on your preferences.