It's completely understandable to feel upset in this situation. Your feelings are valid, and it’s important to acknowledge them. Let’s break down the reasons why you might feel this way and explore the dynamics of your relationship.

1. Previous Conversations: You mentioned that you and your boyfriend had discussed going to Paris together. This creates an expectation, and when he chooses to go with friends instead, it can feel like he is disregarding that shared dream. The emotional weight of a trip like Paris, especially for his first time, adds to the disappointment. It’s not just about the destination; it’s about the experiences and memories you envisioned sharing together.

2. The Context of His Decision: Your boyfriend’s reasoning for not inviting you—stating it would be weird because of the dynamics with his friends—can feel dismissive. It’s natural to want to be included, especially when it involves a trip that you both previously expressed interest in. The fact that he feels it's acceptable to go with his friends while excluding you can create feelings of insecurity and doubt about your place in his life.

3. Comparison with Other Friends: You pointed out that he is going with his best friend and his girlfriend, which suggests a level of comfort and intimacy that you might feel excluded from. It’s important to consider why he feels it’s acceptable to go with them but not with you. This can lead to feelings of being an outsider in his social circle, especially since he has met the mutual friend only a couple of times.

4. Communication Breakdown: The way your boyfriend has responded to your concerns is crucial. If he dismisses your feelings as irrational, it may indicate a lack of understanding or empathy towards your perspective. Healthy communication is key in any relationship. You deserve to have your feelings acknowledged and discussed, rather than being labeled as irrational.

5. Future Considerations: While he mentioned that the trip is months away and you could meet the girlfriend beforehand, that doesn’t negate the feelings you’re currently experiencing. It’s essential to focus on how the situation makes you feel right now rather than what might happen in the future. You might feel that the opportunity to bond with his friends is being taken away from you.

6. Emotional Safety: Feeling upset about this situation also ties into the need for emotional safety in a relationship. You should feel secure and valued by your partner. If your boyfriend’s actions make you feel otherwise, it’s a signal to evaluate the relationship’s dynamics.

In conclusion, you are not crazy for feeling upset. Your feelings stem from unmet expectations, perceived exclusion, and a desire for emotional connection. It might be helpful to have an open and honest conversation with your boyfriend about how his decision makes you feel and explore ways to address your feelings together. Relationships require understanding and compromise, and it’s essential that both partners feel heard and valued.