Non iPhone texts appearing with + before area code even though contact is saved

Hello, my boyfriend is an Android user, and out of no where his texts are coming up as +48 (480 is his area code) and in a separate thread from our original texts. We are unable to text through the original text with his contact. And now it appears he is not receiving any of my texts. I have checked and my SMS is active.

Thank you in advance!

S