How to fix iMessage texting on iPhone?

My fiancé and I aren't able to see eachother and his iMessage isn't working on his iPhone and he is using regular Wi-Fi he uses everyday at his house and when he tries to text my iPhone and it doesn't deliver through to my phone. I need multiple ways to fix this he has tried to reset his Wi-Fi, turn off his Wi-Fi and turn it back on the phone, reset his iMessage and I can't think of anything… Could it be my phone?

Make sure your phone and his phone have iMessage enabled. Go to settings>messages and top option is iMessage. Confirm it's enabled.
Also are you sure you both had Internet at the time of the message?

Imessage is down now for everyone.apple is working on getting it back up as soon as possible.