I can't receive texts from one person...? Any fix suggestions?

This has only been happening for a few days now, but I can't receive texts from my boyfriend. I am getting texts from all my other contacts, and he said everyone else is getting his messages. It just seems to be between the two of us. I have an iPhone 4S updated to ISO7 and he has an android phone (I'm not sure which model)

He said he got my text and replied but I haven't gotten any texts from in the last few days. I deleted his contact, and our mssgs and re-added his number, which didn't help. After googling my problem I tried resetting my network connection (twice) and it didn't work. I checked my blocked list in case I somehow accidentally blocked him, but that's not the case.

So..... I'm not really sure what the problem is. I haven't updated my phone or done anything to it in or before the time I stopped receiving his texts, and this problem is becoming really annoying. Any advice or suggestions are greatly appreciated! :)