Discuss issues/tension or STFU and work on self?

Relationship has taken a downturn. The wife is being extra cold and bitchy despite no fight or any specific reason. How much of an attempt to address her attitude Should be made? Gut tells me best to stfu, lift, not engage with poor behavior and get busy doing things for myself, the household and kids.

Been doing the reading but unclear on how to address situations with conflict. Don't want to be passive if being more assertive and communicating is better.

Also struggling personally to stay engaged because a huge part of me just wants to divorce but due to kids and finances am not sure if I am ready to burn bridges.

At a point where I am going to do my best to focus on self development and decide down the road about whether she makes the cut. Yet I don't want to rugsweep problems so they fester.