My girlfriend 26/F wants to breakup because I’m 27/M is not ready for marriage after 3 years together. What advice can I get?

My girl and I have been dating since 2020 November. (3 and a half years) She’s always wanting to get married young and settle down with kids and becoming a house wife. However, I’ve always wanted to build my career up and be financially stable before marriage and kids. During our 3 and a half years together it has been a rollercoaster, a lot of ups and downs. She’s my first ever girlfriend and I’m her 4 boyfriend.

Fast forward to 2024, I’ve found out that she has been secretly talking to other men on social media and is hiding it from me. I’ve also felt like she’s drifting away and our relationship is going downhill massively. I’ve confronted her about it but she said the men she’s talking to are just friends and nothing serious will happen. However, one day I went through her phone and it seems like she’s flirting with them almost. I felt really uneasy and somehow just let it slide.

2 weeks ago, she told me she is no longer sure about our relationship because I said marriage is not in the picture for at least the next 2 years as I want to focus on myself and my career. She said she wants to find someone to marry her and settle down as quickly as possible.

I’m unsure what to do/ feel in this situation. I love her very much and do what to start a family together with her in the future but definitely now is not the right time. I told her I’m not ready and gave my explanation but it seems like she’s not having it. I do not want to marry her now for the sake of keeping her. I feel like if she doesn’t understand now, we might bump into a lot of issues in the future

We have decided to take a break from each other for 2 weeks. She’s now living with her sister and I miss her so much. Feels like it’s beginning of a heartbreak. I am unsure on what to do. Please share some of your thoughts