I have had beers sit in primary for longer than 1.5 months and it didn't get an infection. This is a sanitization problem not a problem of it sitting on the yeast.
Someone got invited two weeks ahead of time to their friends' house for a lasagna dinner. Two weeks later, when they sat down to eat, the middle of the lasagna was still frozen. The hostess said, "Sorry, I didn't have time to thaw it."
Just an anecdotal reminder that making time to attend to your brew is necessary if you want good beer.