Just make yourself stand in his position. You dont have a absolute majority in the house. You have to take a decision. But many of your party colleagues are against it. Many of your allies are against it. Currently you are helping the nation progress steadily. By resigning you will halt the above and invite un necessary expenditure of mid term poll.
Can you take a decision now. Dont forget the majority of members sitting in the house are the selected representative by the MAJORITY.
A PM have to give priority to what Majority of INDIA wants and not what you or me want.