Wants to Marry a Homosexual
30-4-2003 | IslamWeb
Question:
Can I marry someone who confessed to me that he's a gay (i.e. sexually abnormal) taking into consideration that I believe that I can some how change him by time?
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
Allah Says (what means): {The fornicator does not marry except a [female] fornicator or polytheist, and none marries her except a fornicator or a polytheist, and that has been made unlawful to the believers.} [Quran 24: 3]
This verse is enough evidence that it is forbidden for the chaste women to marry a man who commits Zina (fornication or adultery) or a polytheist and vice versa. No doubt that homosexuality is worse than Zina and it is an even greater sin. This is why Allah punished the homosexuals with the most severe punishment. Allah Says about the people of Loot (may Allah exalt his mention) (what means): {So when Our command came, We made the highest part [of the city] its lowest and rained upon them stones of layered hard clay.} [Quran 11: 82]
So, it is unlawful for a chaste woman to marry an obvious gay who confesses to his perversion and vice. In fact a chaste woman cannot be given in marriage to a homosexual as Allah Says (what means): {Bad statements are for bad people (or bad women for bad men) and bad people for bad statements (or bad men for bad women). Good statements are for good people (or good women for good men) and good people for good statements (or good men for good women)…} [Quran 24: 26]
Ibn Taymiyah 
said: “In this verse, Allah Informs that the bad women are for the bad men. So the good man should not marry a bad woman.”
As for what you mentioned in your question; i.e. that you will help him overcome his sexual problems, this is Satan's whispers to involve you in that which is forbidden by the Sharee’ah.
So, it is unlawful for you to marry him unless he repents fully and he certifies that he gave up this bad habit and feels deep sorrow for what he had done before.
Allah knows best.