Competition between females. That one female 'best friend'. Why do women do this? F/33 M/40

Almost three months of no contact now. It has been an incredibly difficult breakup and healing journey for me, even though I was the one who made the decision to leave.

I left because I couldn’t cope anymore with the constant anxiety, the emotionally unsafe environment, and the feeling that I was never fully the main person in the relationship. His female best friend was always somewhere in the background, indirectly affecting us.

They had an extremely close friendship and had slept together in the past before eventually deciding to remain friends. I’m also fairly sure she had feelings for him. When I met him, I genuinely fell in love. We talked about a future together, having a family, building a home and creating a life together.

But over time, I started noticing how present she already was in his life. There were cards from her around his home, including a photograph of the two of them that she had gifted him. They were constantly in contact, going out for dinners and maintaining this very emotionally involved friendship.

Eventually, it became incredibly triggering for me. I simply couldn’t handle another woman having that level of involvement in my partner’s life.

At one point, I found a conversation between them where they were talking about me. She was constantly reinforcing to him how amazing he was and how I was supposedly “the luckiest girl in the world” to have him. Meanwhile, I felt like I was the one inside the actual relationship trying to build something real with him, communicate through difficult things and encourage emotional growth.

I wasn’t constantly telling him how lucky I was to have him, because for me those feelings come from how someone shows up in the relationship. I needed to feel that he was fully invested in us before I could feel secure enough to express things like that freely.

What I still struggle to understand is why someone would want to be so deeply involved in a man’s life when he is in a serious relationship, without recognising that there is another woman trying to build a partnership with him. For me, there should naturally be some boundaries and space.

I also have a male best friend, but whenever he enters a relationship, I instinctively step back. I give his partner space to become the most important woman in his life.

That was ultimately one of the biggest reasons I left. I felt incredibly insecure and constantly felt like our relationship wasn’t really just about the two of us. There always seemed to be other people emotionally involved in it.

Looking back, I find it almost surreal that I became so deeply entangled in this dynamic.

Since I left, he hasn’t reached out to me once. And one of the hardest parts for me to accept is knowing that he already had emotional support from another woman waiting there. In a way, the role I occupied emotionally could be filled almost immediately after I stepped out, while I was left trying to process the loss of the relationship and everything I thought we were building together.