I have had a boyfriend 4 3 years,but now im startin 2 fall 4 one of his friends? What should I do?

We have been together 3 years,we have a 1 year old daughter.But,a couple of weeks ago he intoduced me to one of his coworker.This whole past week we have been secrelty talking.I cant stop thinking about him.Im now in Florida with some friends and daughter and he the one im crushing on is coming down here tomorrow for vacation.he wants to take me out.My boyfriend is at home working.What should I do,I really like him alot?