this may sound a little strange to you ,but you need to be alone and think about this and write this down

1-why do I want marry this girl?

2-If tommorrow morning she would be afflicted with a terrible condition that would destroy her looks,or perhaps make her look not ugly but perhaps just quite average looking to you,perhaps put on an extra 20 pounds,would you still wish to spend the rest of your life with her?

3-write down all her non-physical maalos.

4-those characteristics that seem to bother you.If you can see that they are part and parcel of her personality,would you be able to accept her as she is,and not harp on them at all,but accept them (and not just tolerate them begrudgingly)

5- is trying to control another person part of your personality?Are you committed to let go of any unhealthy control?

6-would you be able to break your ego to the extent as to be machnia yourself,humble yourself to what she truely is and needs to be?if some of what she wishes to be or if some of her aspirations seem not perfectly aligned with yours,are you willing do still give to her.

can you picture yourself doing very mundane and even boring and even personally distastful acts of chesed for her,just to help her,and doing this,consistantly, even if you will not receive in return? 

7-if you would not need her as a crutch right now,and you no longer need her to fill a void in you,or you just met someone who  now  seems much better looking,finer middos,etc..,how quickly would you dump her?

You need to understand if you really care for this person,what is inside this person,or if you really don't,and your feelings of love is a form of dependency because she makes you feel good when you are around her.

This last point is a very difficult one that must be adressed

because if you end of marrying her,sooner or later all the superficial aspects will wear off, and you will be left with the real person behind the persona that you are viewing.

and that is the deep soul-searching that you need to do now-for your sake and for hers.

It's clear that she has a strong physical and emotional effect on you

strip that away,what is left?

That is what you need to focus on.The real person that is before you,know her well,not just externally,and see if you accept her as she is or not.

there is no quick solution to remove the unhealthy lust towards her.But doing the above will help.

also know that lusting her not only hurts you,you are hurting her as well.

she deserves to be known for who she is, and the lust prevents one from viewing her a person, as a whole entire human being.

So you need to start knowing her from the inside and focus on that as best as you can

hatzlacha rabbah my friend

I wish you the very best