Falling in love only or getting married to someone out of your choice or compulsion doesnt make both of you each other's soul mate or humsafar.you become a soulmate or humsafar to your partner when you are laughing in his/her happiness feeling the same ticklish feeling of joy within you & when sad or hurt feeling the same pain of his/ her without actually being in pain.
Riansh has came a long way in their journey from strangers to enemy to life partners & ultimately to humsafars.the way riddhima felt the pain of vansh on various instances without actually facing it in her own & when she decided to give herself the pain somehow equivalent to vansh she became his soulmate or true humsafar in this journey of life.
The way vansh felt the suffocation of riddhima, her quest to find the truth her desperation her pain without bring actually facing it made him her true hamsafar.
Sorry if anybody feel offended.just expressed my views