Hi there
This is not a good thing to happen to anyone but it's particularly daunting when you are just planning your life (rather than having lived a fair bit of it like me).
But while your concerns are real, take some heart. Lots of us don't die. As a breast care nurse said to me right at the beginning of my diagnosis ( 4 years ago) if you have to have cancer, breast cancer is the best one to have as your chances of surviving are better. Fertility is an enormous worry to carry - I had my only child at 36 and while I had a few thoughts about do I want to? I never gave a thought to what if I can't?? Suddenly facing that possible limitation is a big thing indeed. As everyone will tell you, don't try and work out all the answers at once. Or now. Things will evolve and become clearer, or even different. Especially about transference of any genes. I know of one acquaintance who had treatment and successfully had her healthy baby after treatment. As my surgeon says, we still don't know what causes cancer but we are getting a lot better at treating it.
Your partner cares for you so he will want you to get well. You are not a burden, you are part of his life as he is of yours. Together you can make this a bit easier. Take a deep breath- I had a mastectomy, 17 lymph nodes removed, chemo, Herceptin (HER positive) but my partner never had to become my carer. Had to deal with my frustrations a few times, and a teary night when I accidentally fried my wig ( : ) ) but we went overseas 2 years after treatment, I didn't stop work and I managed OK. How you respond to treatment varies enormously, but it doesn't automatically mean being a burden or the end of love. It's a test you don't want or ask for, but life is a bit like that. 6 -12 months of treatment looms like for ever, but it will pass.
This site can be a great help. Particularly for venting (very therapeutic!). Taking things day by day is hard for everyone, but it's the only way to do it. Try not to worry about the things that haven't happened and focus on how to deal with the things that are real now. True friends and family can be a big support but you may have to tell them what you need, or how you want them to be (they get scared and uncertain too).
Will be thinking of you, take care, take heart.
Alison