What do think i should do?

I just found out that my wife is talking to a guy you used to live next door to her long time ago. He live down south now. Hefound her on face book , at first i thought it was nothing Now all of a sudden i see message,like good morring sweety, hi baby,i be with you if i could and so on She dont know i found this out. I just not sure if i should say any thing, but it is borthering me. And i dont know what she is saying to him .Should i go for the neck? We have been married30 years Tell me what you think is up Thanks for your time