Two possible options.

I have a Google Pixel, so I don't know if this will work for you or not. Go to your account on your carrier's website and look at your call/text history. Verizon shows a list of all incoming and outgoing texts. You can find the number that way. Next, go in your message app and start a new text to that number. My phone automatically shows the past text history whenever I do that, even if I deleted that thread of messages. You don't have to actually hit send. Just typing in the box causes the old messages to pop up.

Your other option is to try installing a different text app. I switched from the default one to Textra, and when I hit "make default" all of my old messages carried over to the new one including recently deleted messages.

You can do a word search. If you remember any phrase-search your texts. on an iphone its at the top

if you have an iphone AND imessages turned on your computer or ipad, it might still be on one of those devices.

If you don't have his number that means it's not saved. He can't just send a text from an unknown number and expect it will be seen. Just ignore until he brings it up. It's his job as sender to make sure it's a valid communication channel.

It’s gone hon. Deleting a text it’s gone foevef

I saw a notification today of what I think was a text (guess it could have been an email) on my phone from my former boss. It was about something important and I was grabbing my phone to jump in the car to shuttle a kid, so I figured I'd read it more closely when I got home and respond. But now I can't find any trace of it. The only thing I can imagine is that I somehow inadvertently deleted it when I was holding my phone. Or maybe he deleted the text after sending it. Either way, is there any hope of figuring this out or finding some trace of the notification? I don't even have his number so the most I could do would be to email and say, hey did you just text me? which feels sort of creepy.