All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, we ask Allaah to bless you with ‘Eemaan (faith) and certainty and make you firm upon the truth.
You are obliged to take the initiative to repent and you should know that if you are sincere in your actions, Allaah will enable you to do them. So, He will accept your repentance and enable you to be firm on it. For more benefit, please refer to Fatwa 87903.
Moreover, you should know that the Mercy of Allaah is vast, so you should not let despair enter your heart, as Allaah Says (what means): {Say, “O My servants who have transgressed against themselves [by sinning] do not despair of the Mercy of Allaah. Indeed, Allaah forgives all sins. Indeed, it is He Who is the Oft-Forgiving, the Most Merciful.}[Quran 39:53] For more benefit, please refer to Fataawa 88108 and 83055.
There are some objectives that you should endeavor to achieve, among which are the following:
a) Avoiding such tricky relationships.
b) Keeping company with righteous women.
c) Attending lectures and circles of knowledge.
As regards those thoughts that you have, they are from the devil who wants to drive you away from righteousness, so you should not pay attention to these whispers. You should continue to repel them and say: “Praise be to Allaah that the plots of the devil are nothing but whispers.”
If you are still attached to that first man, then there are some means to treat love sickness as explained in Fatwa 84544.
Also, you should remember that this man did with you what you said despite the fact that he is your relative, so you should not expect anything good from him.
As regards the other young man, since he is religious, you should accept him as a husband as the Prophet said: “If a man whose religion and moral character are pleasing to you proposes to you, then let him marry.” [At-Tirmithi]
Concerning your statement that you feel that you are inappropriate for him, if you mean that this is because of the sins you have committed, then this, on the contrary, should be a reason for accepting him as a husband so that he will help you in performing good deeds.
Moreover, you should know that a person who repents is like a person who has never committed a sin as confirmed in a Hadeeth of the Prophet . Rather, you should know that a person who repents, is beloved by Allaah; Allaah Says (what means): {Truly, Allaah loves those who turn unto Him in repentance.}[Quran 2:222]
Allaah Knows best.