I (27 enby AMAB) started seeing D (24 F) last month.

I come from a long period of abstinence and last year has been the first year I started dating since 2019. I went out with a lot of women but never really kissed anyone except 3 girls, included her. In my past relation, I had sexual performance anxiety that basically ruined the relationship (together with bad communication), so in the past 5 years I mostly worked on myself and took thing slowly, and it is working.

I really felt good with D. We kissed on the first date and had sex in the second. She was really able to reassure me about my sexual anxiety, and I felt really good with her, so I grew attached. I have a disorganized attachment, and started thinking about ENM some weeks prior I started seeing her because I wanted to explore myself more deeply in relationships and I thought "since I have been alone for the last 5 years and for the most of the time, ENM could be good to explore myself more, mantain my independence and dealing better with my insecure attachment since the cheating aspect is not really present and have not to worry about other people since it's all in the rules of the relationship". We can say I probably have disorganized attachment with some sparkles of secure attachment especially when the other person acts anxious (I feel secure to reassure anxious people since I know anxiety really well).

This month I had to go to the other side of the world for work, for about 3 weeks. We didn't really talk that much and I started to feel really anxious and unimportant. I talked with her about me needing her more present since I was so far away and felt so alone (I was basically in a small country with about 200.000 people in the entire country and like 20.000 people in the city I was). She listened to me and reassured me, and I was overall okay. We organized one day in the week to make a videocall to be more present.

I returned last week and yesterday we met, she stayed at my home for the night. I felt a bit disconnected about her. She told me she was tired about university and didn't really listen to me, and interrupted me often. She look tired when I vented about my work (I have some problems there) and told me that she would've interrupted because didn't want all that negativity. I could understand that, but don't really knew how I felt (I have been gaslighted in my last relationship so some times I don't really know what I feel, if I did something wrong or over-exaggerated).

We weren't that connected during sex, too. It was not bad, but we had some physical disconnection and I lost my erection so we stopped.

When I accompanied her home she talked me about a guy she was dating last month, with which she had some problems and was also gaslighted. I felt really sorry about her, but she ended closing things with this guy since it was becoming toxic, so I am happy about this.
However, there was a detail I was not really happy about. While I was away for work, they tried monogamy and she didn't tell me up until today. I felt really sad and hurt and couldn't give enough empathy to her to support her venting about this toxic situation.
Even if she ended things with him before I returned, I felt hurt because she didn't tell me she wanted to try monogamy with this guy. We still are not officially in a relationship, but she told me before she looked at me as a potential partner and I was not an only-sex person and we had some emotional things going on.

When I told her "what if the monogamy thing worked on?", she got upset and told me that didn't happen in the end and I was away and I should have returned at the end of the next month so she had a lot of time to decide.
I told her that even if it didn't happen, in a non-monogamy it is important to be clear to all partners when you are deciding to change the relationship style, ESPECIALLY if you want to close the relationship with another one? Especially when I talked a lot about my insecurities, thinking at the time that she really listened to me about them.
She told me that she still doesn't see me as a partner and is starting to seeing a new guy, called B, with which she really is fond of.
I told her that since she is the only one I am currently seeing, for me she is important. And especially I don't want a hierarchical thing whether I am a primary or secondary partner.
She told me that both me and the other guy are important in different ways, but I sort of understood that she sees this guy as a partner, and not me.

To be honest, I felt a bit of resentful and cheated on when thinking about the monogamy intentions with the toxic guy.

Is it wrong for me to expect it to communicate that even if we're only at the start, since emotions are involved?

Is it wrong for me to being a bit upset if she met B. a few weeks ago and is more involved with him than with me? Seeing him more as a partner than me when we are seeing each other from a month? Tbh I am not jelous about him because he really supported her with the drama with the toxic guy.

Maybe I am over exaggerationg, but I am starting to have a lot of doubts about this thing. I don't feel listened and don't really feel safe anymore to look vulnerable with her.

I am starting thinking that I need and want a person that is there for me as much as I am there for her. I don't know if just to ease my expectations with her and take things really slowly, reducing my emotional involvement, but I don't know if I can feel secure with her ever again.

What do you think? Am I overreacting?

PS: Sorry for the bad english, not a mothertongue :P