In love,but Pained

 I recently picked my wife's phone to make a call, because had a low battery. She comfortably handed me the phone. Upon receiving the phone I saw an unread message from what I later found out was a guy since My wife had saved his name with a lady's name.

I wasn't going to open it but because of the nature of the message, I was forced to read the entire conversation. The unread message on her screen was {I will do anything for you sweetie}.

I know a woman can send that message but my instincts were telling me to confirm the gender from their chat. 

They had a long history chat. And calls. I discovered something that shocked me.

It was from their interactions last year when my daughter was born. 

When my wife was in the labor ward, I was leading a presentation for our company.

In fact, when my wife forwarded the picture of my daughter to me on WhatsApp, was about to give a speech at the meeting. I was so excited, i had to announce to everyone l had a daughter. I used FORWARDED because she originally had uploaded the picture to this man and captioned it, {Our baby girl).

I took my phone to scroll to see the time she forwarded and found out My daughter’s name that we now call her was suggested in their chat by this man. 

I feel so embarrassed, ashamed and betrayed. 

I don’t what to do next😭😭😭

Please advise me