Negotiating a salary is scary for some, and easy for others. Most of us choose to forgo negotiating. I, personally, always dreaded this part of job interviews, even though I love to bargain. From a boss’s point of view I have to admit that I am always interested to see if a candidate will bring up a question about money. Right off the bat, I will tell you this: do not discuss money until a job offer is made. Otherwise, I (as a boss) lose respect for you.
Let’s be honest, you are going to tell your manager about this job offer because you want a counter offer, some sort of monetary acknowledgment of your value to the company. You like your job, you just want more money, right? So to answer your last question, I am going to say “yes.” There is a very strong possibility that your manager will think that you are trying to extort a raise by threatening to leave.