The evidence in your case is what counts. The party with the most complete records, photos, videos, texts and emails has a very big advantage in court. If you are more organized and have a command of the facts, you will help improve the strength of your case by leaps and bounds over your spouse. If you are able to summarize and digest the evidence into charts and spreadsheets, you will improve your case even more.
Don't worry about whether you need to file first. Worry about how you are conducting yourself and whether your conduct is going to hurt or help your case.
The difference between an ideal outcome in court and a poor outcome often comes down to how you present yourself and how you come across to the Judge. Focus on the facts, the evidence, your witnesses and yourself and it won't matter who files for divorce first.