You're right. In season 1 and 2, Teresa and Joe seemed genuinely in love. Especially when she was expecting Adriana and then their family trip to Italy - I loved watching them.

In season 3, when Melissa and Joey joined the show... You could tell Teresa was hurt/uncomfortable with the situation. Because now, HER issues with her immediate family would be put under a microscope.

Teresa seemed stressed out by that PLUS I think that was around the same time that her and Joe started having legal problems. Tre and Joe's relationship was put into a pressure cooker. And that's when I saw Joe start to openly treat Teresa like garbage. On and off camera.