Is My Mental Health Ruining My Relationship

I (21F) have been struggling with my mental health since before my partner (24F) and I even started dating. I've always had persistent thoughts of suicide and self harm. It's something I struggle with daily. Lately I've been feeling that my mental health is causing too heavy of a strain on our relationship. My partner lost her mother to suicide, and I've always felt guilty for making her deal with all of my mental struggles, as I'm sure it's all extremely triggering.

In the 3 years we've been together, I feel that I haven't come anywhere near close to getting better. I've been in therapy in the past, and I'm on medications for depression and anxiety; unfortunately I lost my insurance and could no longer afford therapy, or an appointment to talk about better medications. I don't feel it's fair for her to keep waiting for me to get better. She's always been very adamant about staying with me and encouraging me to get better, but when do I know if it's a lost cause? We have plans to marry each other one day, and live the rest of our lives with each other. But what if the effects of my mental health on our relationship is robbing her of her opportunities to live a truly happy and worry free life? How do I know when to say it isn't fair to her? I feel that by allowing this relationship to continue, I will be hurting her in the process. What is more damaging? A break up, or watching your partner constantly lose in a battle against their mental health. I don't know what the right thing to do is. Do I trust her when she says she loves me, and still wants to be with me despite my mental struggles? Am I just in my head? I don't know if it's fair for me to allow her to stay and wait for me to get better.

I only want the best for her the way she wants the best for me. But sometimes I wonder if she'd be happier with someone who doesn't struggle the way I do. I'm always afraid I'm not the person she needs me to be, or the person she deserves to share her life with. I'm always afraid that she'll realize she's unhappy just waiting for me to get better. When do I know if my mental health has ruined my relationship?