Trust me you are not alone with your battle against the flesh. Even the apostle Paul had similar feelings. Look what he wrote at Romans 7: 21-25.
..."I find, then, this law in my case: that when I wish to do what is right, what is bad is present with me....I really delight in the law of God according to the man I am within,...but I behold in my members another law warring against the law of my mind and leading me captive to sin's law...Miserable man that I am!...Who will rescue me from the body undergoing this death?...Thanks to God through Jesus Christ our Lord! So then with my mind myself I am a slave to God's law, but with my flesh to sin's law."
God knows how imperfect we are and provided his son's ransom sacrifice to cover over our sins if we are truly repentant and keep trying to make the necessary changes. Pray before if you can and you will get help beyond what is normal to overcome these wrong desires.
As to why God has permitted this condition on the earth for mankind, be assured it is temporary, and God's original purpose of having a paradise on earth, with perfect humans, has not changed. It will soon come about by means of God's Kingdom or government which is all set to take charge of the earth. Dan. 2:44. Matt 6:9,10
You can read more about Why God's permitted wickedness on the earth in this book distributed for free by Jehovah's Witnesses. It will answer all your questions with the bible.
the publication; what does the bible really teach? Chapter 3 and 11