iPhone sending texts to Apple Message, not phones

I've run into this problem before, and it's usually that the phone number has some how become dissociated with iCloud but the email has not.

If, in iOS, you go to Settings / FaceTime, you'll see a "You can be reached by Facetime at" and this will often show if your phone number is even associated or activated.

Likewise, go to Settings / Messages / Send & Receive / > and see if appears there.

See https://support.apple.com/en-us/HT201349 for details about adding numbers.

Your wife needs to go to the messages app on her phone, go into the conversation with you, tap your name on top, then "Info", then your name again (why Apple) and on this screen it should say "Last contacts" next to your phone number. If "Last contacts" is next to your email address, your wife sends iMessages via email, which is possible but obviously doesn’t work with your Android phone. In the latter case she needs to create a new conversation with you, and this time specifically choose your phone number.