Yes.
Simply having a boyfriend doesn’t preclude you from developing feelings for someone else.
You are still human after all.
If you were to get really close with another guy through work or through some kind of circumstance, you can easily begin to develop feelings for that guy.
The more time you spend with that guy, the more likely the feelings will deepen.
This is even more likely to happen when there is something missing in your own relationship with your boyfriend.
You may believe that your boyfriend has been taking you for granted or has been showing you a lack of affection.
Your boyfriend may be constantly procrastinating on things that he has told you that he will do for you.
Your boyfriend may even have some anger or depression issues that you have been trying to deal with since you started dating him.
Perhaps you are trying to work through all these problems.
Perhaps you love your boyfriend and believe that you should just try to be patient and things will improve.
Perhaps he will become more affectionate or stop taking the relationship for granted.
Perhaps he will learn to handle his anger or depression in a better way.
So you wait it out and hope.
However, as time has gone on, nothing has changed.
You are becoming anxious and even a little irritated.
In comes this other guy.
You get close to him at work or at some function that you are a part of.
He seems so in tune with what makes you smile or content.
He is attentive to what you have to say.
He compliments your beauty or charm.
He makes you start feeling more excited about life in general.
Perhaps you begin to confide in this guy about your home life with your boyfriend.
He is attentive and is willing to give you some advice.
The more he is open to your discussions and willing to give you advice, the more you confide in him.
Before you know it, you realize that you have now developed feelings for this other guy.
You look forward to seeing him at work or wherever you tend to see him.
You may start going out of your way to put on some extra make-up or dress a little bit sexier.
Perhaps he will notice that and give you a compliment.
This is how this scenario typically plays out.
On the flip side, the relationship that you are currently in with your boyfriend may appear to be good on the surface.
It may appear as though all your needs are being met.
However, there is clearly something missing.
You are not being fulfilled in some way.
You may try to deny this because you are very good at masking your true emotion.
However, all that masking only reflects the reality of your true emotions back on you whenever you think about this other guy and his image puts a smile on your face.
No matter how perfect your relationship with your boyfriend may appear to be on the surface, it is not so perfect underneath.
This may be something that can be remedied through working through it with a willing boyfriend.
Then again, it may be something that can never be remedied because the damage is too severe and your emotions have moved on to someone else.