Do you think i should take the plan b pill if my partner had s vasectomy and was cleared by the doctor?

No: Pregnancy is not completely impossible after a vasectomy, but it is so unlikely that taking Plan B would be considered not only unnecessary, but more potentially harmful than helpful. While Plan B is a very safe medication for most women, all medications have some potential for side-effects, and when there's little to no potential for benefit then medication simply shouldn't be taken.