My condolences. A miscarriage is always sad, and there is little comfort to be found. What you both need is someone to listen to you, without judging your grief and without trying to belittle your loss. Unfortunately most people tend to try and comfort you with irrelevant phrases.
I'm not familiar with this state of the relationship, but you have both lost your child even if you're separated. If she can find comfort with you, and you can find comfort with her, you should probably try to go through this together. If she wants you to leave her alone, respect her wishes, and try to find solace somewhere else.
In any case, in most miscarriages, the physical comfort passes after a few days, or a couple of weeks, but the emotional scarring could get longer to heal.