I forget where I read it at, but it's a solid bit of advice:

When you have a problem in the relationship don't let it go longer than 2 weeks before getting to the root of it and getting things back on track. The longer you let things slide, the harder it'll be to remedy things.

This seems like common sense, but so many times I've seen it in my own relationships where I sensed something was off, but didn't take action for one reason or another. You've got to bite the bullet and call out the issue at hand, because ignoring it will just make things worse. 2 weeks is your optimal window for resolution before things get out of hand.

edit: It was Athol Kay

So the rule is simple… Anytime you notice your partner being usually moody, odd, avoidant or devious with you, never let it go on more than two weeks without getting to the bottom of it.