Questioning my realationship

Questioning my realationship
Hi all, looking for some advice on my realationship with my wife.
recently my wife has been coming home late from work, not by much anywhere from 30 to 45 mins,
this coming from a women who is usually very punctual, and other changes like she stopped calling me at her lunch time or when she does she rushes me off the phone she has even disconnected the call if i called her,
when i asked her about it she said it was just due to spending time with friends (co-workers)
but i guess i let my suspicious mind get the better of me and i did something i should not have, i checked her cell and sure enough there were text msgs to and from a male co-worker one of the msgs read that she didnt know what to do with the way she felt,
anyway to make a long story short, i confronted her, she was pissed that i looked in her cell but after a long talk she admitted that she had strong feelings for this guy but that i should not worry becouse she said she would never cross that line and has not,
he is just a very close friend accourding to her but im still very worried, should i be concerned and what would others do in this case.