13 years together/how do I save my relationship

I’ve been with my fiancée for 13 years. During the first seven years of our relationship, we both hurt each other through infidelity, which created a lot of trauma and trust issues between us. For the last six years, I’ve been loyal and committed to her.

Recently, her mother passed away. I’ve never experienced a loss like that before, and I didn’t know how to support her through such deep grief. Looking back, I understand why that hurt her. She felt like I should have learned more about grief and how to be there for her. As time went on, the pain, accusations, and emotional distance between us caused me to shut down emotionally and become withdrawn.

Because of our history, she began to believe I was being unfaithful again. Over time, every situation she saw or every concern she had felt like proof to her, no matter what I said. I was frequently accused of looking at other women, being too friendly toward women, or wanting attention from other women. Eventually, those accusations affected me so much that I became hesitant to have any interaction with women at all, despite having no intentions beyond being respectful.

Around Christmas, she asked me about a girl from a video game. The truth is that I had only played with her a few times because she was occasionally in a gaming party with some of the guys I play with. Instead of telling the truth, I lied and said I didn’t know who she was and had never played with her. That was wrong.

My fiancée ended up leaving and taking the children to stay with her parents. I was ashamed and embarrassed by my lie, and instead of immediately correcting it, I held onto it for a couple more months before finally admitting the truth. Now, because I lied and because I allowed that lie to continue for so long, she believes there must be more to the story than there really is.

Since then, everything that has happened and everything she has been told has only reinforced her belief that I was hiding something bigger. From her perspective, her experiences and the pain she has lived through make it difficult for her to accept what I’m saying now.

The truth is that I never had a relationship with this girl, never met her, and never had any intentions beyond occasionally being in the same gaming party. My biggest mistake was not being honest from the start.

Right now, I feel lost. I understand why she struggles to trust me, but I don’t know how to help her see the truth. I don’t know how to show her that, despite my mistake and poor decision to lie, I have been loyal to her. I love her deeply and want to rebuild the trust I’ve damaged, but I’m struggling to figure out how to do that.