I am too young to give relationship advice to someone who has been in a relationship for 7 years. But I would like to help you if I can.
See, you have been in a relationship with your partner for seven years. Seven years is a long time to understand the person and even accept or embrace them. So, if your habit is not new even if it is somewhat bad, then your partner doesn't really care about your habit because he spent seven years with you knowing that. Also, no one is perfect. We embrace the imperfections of people knowingly. Seven years is a long time for that. So stop blaming yourself.
Clearly, you love him and want to be with him. Still, before you do anything, ask yourself if you really love him. Now the question arises how to convince him to talk to you. It is the most difficult part because usually, proper communication wipes out all the misunderstandings and help us see things clearly. You may call or text him to meet. If he is ignoring your calls, you may contact his friend and ask him to help you talk to him once at least. You may wait outside his office or apartment if you want to.
Since he says that the reputation of his family is at stake, then you can try to meet his family, with or without him, and tell them about your relationship with him and how he is going to marry someone else only because he thinks if the alliance is cancelled, his family's name would be spoiled.
You should also mention to him or to his family, whoever you meet, what your partner said. He clearly said that he knows no one would be happy if he marries the other girl. When he knows this, then why is he hell-bent on ruining not just three lives but three families? Marriage doesn't happen between two people but two families unite. In your case, three families will get affected, if because of a small issue, such a big step is taken. Ask him politely to keep his ego aside and think where does he see himself in the next 10 years and with who? Tell him relationships take years to grow and become strong. Tell him you want to be with him and that you love him.
But even after all this, he doesn't understand and refuse to be with you, then I am sorry to say that he is using the reputation of his family as an excuse to break all bonds from you, without tainting his own image. He is perhaps over you and doesn't want to be with you anymore.
And it may seem hard to digest this fact, but you need to understand that you are important, you have self-respect, for saving your relationship you did every possible thing, and the most important thing- It was not your fault.
All the best. May the Lord guide you towards happiness.
Make love to life before it divorces you.