So how to keep yourself motivated is a really great question. Initially my first streak was actually 8 months abstinence but at 5 months I introduced orgasm with a partner. The most important aspect of maintaining abstinence for me is the mindset.
My mindset is that I don't want to P, M or O regardless of rebooting ect. When I abstain I have more time, more energy, and I am kept in better spirits. So now I just don't relapse. When abstinence is the only option then you don't have as much time to wonder whether you are going to relapse, and that thought of 'This is all pointless, I may as well MO' goes away because it isn't an option anymore.
I also have various point in my life where I know porn has impacted, and these have been reaffirmed by things such as the flatline that porn has damaged me. Think up some times in your life that reaffirm what porn has done to you and you won't relapse
My other bit of advice is too start getting excited and motivated. You're starting a really great process which will hopefully allow you to make massive beneficial changes to your life! Start finding things you want to be better at!
I started exploring new passions in life, some of which I wrote in my post here, such as meditation which I am constantly refining and adapting too. Find your own way to focus on other things than PMO and recovery. For instance spending time with your girlfriend! Challenge yourself to go do something completely new this week!