Does it require enough courage to file for divorce?Yes, it takes tremendous courage for the average person to engage in any kind of legal proceedings, and divorce is one of the most difficult. The child is definitely a factor. I don't know where you are, but I've recently learned just how strange divorce law can be in some states and countries. If you're even thinking about it, be sure you have researched thoroughly before you make that final leap.
As my attorney told me when I discussed my divorce plans early on, every divorce, no matter how friendly, winds up as a battle of wills. So you have to be prepared to face that. It's also very expensive in the US in pretty much every state. I thought my daughter would have an easy time of it in her state where the law is very firm with minimal wiggle room and divorce becomes final in only 60 days. I was wrong. My divorce started as a relatively friendly plan to split up with an agreement we'd written prior to even consulting attorneys. I thought it would remain friendly It did not.
The aftermath in terms of both financial impact and the reality of splitting custody of a child or explaining to a child why it happened and that it wasn't his/her fault is incredibly difficult for most people. I know there are folks--mostly people high in the business world who are used to such negotiations--who fly through the process and are on to the next relationship before the ink is dry on the decree. They are in the minority.
If you are concerned about your wife's behavior or there are some issues that make you think you need to live separately, consider the possibility of a Separate Maintenance Agreement. You would continue to share finances and custody of the child but live separately. This is a binding legal agreement and can easily be swapped later for a full-blown divorce if that seems appropriate. It's less expensive in terms of legal fees as there are fewer court costs and everything can be worked out between the parties' attorneys. But it only works if both parties are responsible and reliable and willing to work together without purposely creating havoc for one another.