Many people take the easy way out and just forget their spouses mistakes, move on from them, put them in the past. But is that always the right way to handle things? Sometimes saying "its okay honey" may give your partner the idea its okay to do it again. Therefore, past mistakes will reoccur over time. So holding a grudge against something you don't feel is right makes more sense and will lead to less problems in the future then just forgiving right away. Study's show that marriages who are very forgiving of there spouse tend to fight more then others who don't let their partner off the hook as easy for the reason that the behaviors of the unforgiving spouse will be better because they want to be forgiven. Scientists also found that couples who are more forgiving have troubles with their spouses behavior the next day, twice as much as couples who hold the grudge. This isn't saying to never forgive your spouse, just sometimes being tougher on your loved one will benefit in the long run. In my opinion being less forgiving will lead to fewer problems based on research results.
I got my information from: http://www.livescience.com/culture/forgiveness-bad-for-relationships-110107.html