I use the word Covet (which I'm going to try to bring back into use, since it is all encompassing), because when I see a girl that I find attractive, the process of thought goes something like this:
1) Acknowledge her natural beauty, the affirmation that she is attractive
nothing wrong here! - - except, maybe your use of the word "covet." The first definition above describes a strong yearning. In the second definition, it is a desire for something that belongs to another. In your example, are we wife-coveting or coveting someone's girlfriend?
2) Begin to look at her further
still OK. So far, so good!
3) Begin to consider her as girlfriend material
4) Begin to entertain thoughts of her as girlfriend material
What do both of these mean? Is one innocent and the other lustful? Yer losin' me...
Ok STOP (hammer time).
When 4 begins, ASK YOURSELF:
"Am I attractive enough for this girl? Would this girl be disgusted if she was to know that I was entertaining thoughts of her being my girlfriend?"
If I'm not attractive enough to be the girl's boyfriend, I put those thoughts out of my head out of respect for her.
She would die if she knew I thought of her as a girlfriend.
Why would she be disgusted? What thoughts are you entertaining? "...thoughts of her being my girlfriend?" is very unclear - - if you are fantasizing about sexual things with her, those should not be part of boyfriend/girlfriend activities among believers.
oh, and have we even talked to this girl yet? All we have so far is that she is physically attractive.
5) Begin to covet her as a girlfriend
Pause for a second. You see a cute girl, and you reach stage 5. Then you start actually thinking of what it would be like for her to be your girlfriend, and you feel that positive, happy feeling. This is where I usually run, if I haven't already at step 4.
These thoughts aren't healthy! They'll lead to tears later when you discover she could never have been your girlfriend in the first place.
How come she could never be your girlfriend?
Save yourself from a broken heart. Stop thinking of her in that way.
Why are you so quick to assume rejection?
6) Pursue her
If you've reached the point where you consider her girlfriend material, then your mind will begin to figure out how it can make those thoughts a reality. You will think about her when she's not around. You will do things that will increase your chances of her being in your environment. Worst of all, you will be nicer to her than you will other people. You will be biased towards her and your relationships with other people will suffer, because you show her preference over others.
AND SHE'S NOT EVEN YOUR SPOUSE.
Again, have we even talked to her yet, or are we admiring her from afar? If we are in a relationship, then yes, she will get preferential treatment.
7) Lust for her
Now you've done it.
You let yourself enjoy thinking about her just being your girlfriend.
And that wasn't enough. You didn't stop yourself.
So you began to actually consider her as your girlfriend, and you stored up hope of this by consenting that those thoughts would be good to happen.
Then, your mind began to work to bring these thoughts to reality. And you changed your life, and sacrificed your existing relationships to accomodate and show preferential treatment towards this girl.
And now your mind is going to pursue her as a spouse. And your relationships will suffer in some way.
And you might even act out according to your lust.
So does admiring a woman always lead to lust, or can it lead to a healthy friendship or romantic relationship?
That's why I say RUN.