It can be hurtful and confusing to see an ex-partner doing things with their new girlfriend that they didn't do with you during your relationship. While I can't know the specific reasons for your ex's behavior in your situation, I can offer some possible explanations that may shed some light on this behavior:
Different stages of life: People change and evolve over time. It's possible that your ex is at a different stage in his life now and has different priorities and interests. What he didn't do with you might align with his current life circumstances or personal growth.
Learning from past mistakes: Your ex might have learned from his previous relationship with you and is trying to be a better partner in his new relationship. This could include making an effort to engage in activities or behaviors that he didn't prioritize before.
Compatibility and shared interests: It's possible that your ex and his new girlfriend have more shared interests or hobbies that naturally lead them to do certain activities together.
Trying to impress: In the early stages of a new relationship, people often try to impress their partners by doing special things or going on exciting adventures. This behavior might be more pronounced in a new relationship compared to a long-term one.
Different dynamics: Every relationship has its unique dynamics, and what one couple enjoys doing together might not be the same as what another couple prefers. Your ex's new relationship might have a different dynamic that leads to different activities.
Avoiding comparisons: Your ex might be consciously or subconsciously avoiding comparisons between the old and new relationships, trying to create a fresh start without the baggage of the past.
It's essential to remember that every relationship is unique, and comparing yourself or your past experiences with your ex's current situation may not be helpful. Focus on your own growth, healing, and happiness moving forward.
If you find that these feelings are affecting your well-being or self-esteem, consider seeking support from friends, family, or a professional counselor to help you process your emotions and move forward in a positive direction. Remember that healing takes time, and it's okay to take things at your own pace.