Let me see if I got this right..

hum... well Jacob had this feeling for her. This strong pull. He forced himself to try and imprint himself in New Moon. But it's not something that can be forced. That particular feeling was his feeling for Nessie. Please correct me if I'm wrong. haha

The need they felt to be together was because of nessie's upcoming birth. They thought it was because they loved eachother but it was That Nessie was coming but Jacob didn't know that. Its weird but its like Jacob was having a preminition but didn't see it till Nessie was born.

Becoz jacob inprinted on renesme

well jake imprinted on renesmee so he just liked bella as a friend...and bella had fallen completely in Amore with edward after eclipse and especially after the wedding and she too wanted jakob to be only her best friend... so their relationship balanced!

Jacob didn't feel the desperate need for Bella because he imprinted on Nessie.