All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, is His slave and Messenger.
Shaving pubic hair is among the acts which Islam encouraged people to do. The Muslims are not permitted to abandon shaving the pubic hair for more than forty days. Anas said: “A time limit was prescribed for us (by the Prophet ) for trimming the moustache, cutting the nails, plucking the armpit hair, and shaving the pubes; we were ordered to not leave that for more than forty nights.” [Muslim]
The forbiddance in this regard indicates prohibition of the act [i.e. abandoning it more than 40 days], as stated by some scholars. Ash-Shawkaani, may Allaah have mercy upon him, said in Nayl Al-Awtaar:
“Rather, the chosen opinion in this regard is that one should adhere to the (time limit of) forty days set by the Prophet and it is impermissible to delay these acts beyond forty days. A person who delays trimming his mustache or any of the other acts, even if they grow long, until the end of the time limit is not considered to be contradicting the Sunnah.” [End of Quote]
Based on the above, it is impermissible for you to abandon shaving the pubic hair for more than forty days. Your fear of committing a sin is due to Satanic whisperings. Therefore, you should follow the Sunnah and strive to discard such forbidden thoughts and refrain from responding to them.
For more benefit on shaving pubic hair, please refer to Fataawa 92643, 90908, 86976, and 81607.
Allah knows best.