Yes you must eliminate sexual desire for a complete union with God, whatever religion you may believe in. I am a Hindu, and we have a saying, Rama (whom the Hindus believe to be an incarnation of God) is not there where lust lasts. You can do it by following ways.

1. Try yoga. Emphasize on Mulabandha Mudra, and Uddiyanbandha Mudra. Get yourself a guru for these.

2. Have faith on whom you worship - God, Allah, Krishna, whoever. Sex urges hinder the paths of even greatest saints so don't give up even after repeated failures. Just pray so that God takes it off. Don't complain to much. Don't give much attention to it, or it will increase. Don't lower your vision to sex; look above!

3. When you feel an urge, remove the object of the urge or leave the place. Without the object, your urge will not normally last more than five minutes. Gently tell your mind that you are not going to succumb to lust a few times, then simply concentrate on another thing. Remember, don't linger back to the thought and most importantly don't try to fight too much with the urge. Just, casually move to some other work. Do any or all of these things if possible -

If outside home - take a stroll / watch people in the street / sit somewhere and look up at the sky

If at home - Take one or two glasses of water / take a fruit / breathe long for 20-25 times / Sit in the above mentioned yoga postures / Take any spiritual book and read some paragraphs / sing a carol or chant a prayer in low voice / feel that you are the boss of your mind and sex urge is not going to overpower you.

I have been doing these things for last ten-twelve months and my life has improved significantly. If this works, find me out in Facebook (my full name is Kumaraditya Sarkar, I am from Kolkata, West Bengal, India) and we will discuss further.

May there be peace all around!

Regards,
Kumar.