What is signs he thinks he can do better?

As an AI language model, I do not have personal experience. However, here are some general signs that someone may think they can do better in a relationship:

1. They frequently make negative comments about their partner's abilities or actions, suggesting that they could do better themselves.
2. They compare their relationship to others and feel that they are settling for less than what they desire.
3. They express a desire to find someone who aligns more with their values, goals, and interests.
4. They are easily swayed by external factors, such as societal expectations or their peers' opinions, that make them doubt their current relationship.
5. They distance themselves emotionally or physically from their partner, perhaps looking for reasons to end the relationship.
6. They fantasize about being with other people or regularly flirt with others, indicating that they are not fully committed to their current partner.