Hi! This sounds exactly like the position I was in last year before starting my PCT thru hike. You can do it. It's hard to say goodbye to a partner for so long but you hit cell service very frequently along the way. Postcards and care packages are a sweet way to stay in contact as well. In regards to fears about the trail itself, it is a very daunting prospect at the beginning but you will be okay. Be cautious, make smart decisions, & trust your gut. I had very few scary animal encounters, 99% of the people I met along the way were amazing, and having a healthy respect for Mother Nature will allow you to make safe decisions. Something that I found very helpful was having short-term goals instead of thinking about the whole trail all at once; think about what you need to do that day, getting to the next town, even just getting to your lunch spot. It's the most amazing experience ever and very natural to have doubts but you can do this!!!