I agree with what you are saying, but this serial is all about Sarab/Meher, so that is why I feel Karan will stay with them.
Also, Manav hasn't been honest with Aditi and Seema (he didn't tell the whole truth to her) and sneaked behind them to get Karan's DNA test done and took assistance from Robbie and Partak.
Just kill his character again.
Cant digest his maximum screen time and cry baby face all the time.
ENOUGH OF THIS USELESS MANAV CHARACTER END IT ALREADY
LOL I hate him ugh.