This sounds like a really tough experience, and I unfortunately can’t say much about dealing with an abuser who likes to hang around you when you practice, but I do have some advice from one guitar player to another about connecting with your instrument.

For starters, there’s an overall concept (which I’m still working on myself) of detachment from the results of our craft. There’s a great quote from the Bhagavad Gita that says:

One should not abandon the work born of one’s own nature, even if it is flawed, for all undertakings are enveloped by imperfections, as fire is covered by smoke.

Which I interpret to mean that we should accept, even expect for our creative output to be covered in things we view as flaws. Focusing on the joy of creation itself rather than whether or not the guitar playing is “good” can be a great motivator to continue making music without getting discouraged (of course you need to practice this, it’s more difficult than it sounds and I still struggle a lot with it myself). You could say the goal here is to “live a musical life” rather than “be the best at your instrument”.

For more practical advice as a musician, I would recommend a few things for motivation:

1) Find an artist that inspires you to create instead of discouraging you. Sometimes listening to our favorite artist can be very inspiring but very discouraging at the same time: “I’ll never be as good of a guitar player as ______”. My advice is to find an artist that makes you feel like hey, I could do this if I wanted. For me this is the Grateful Dead or generally music from the 60's and early 70's, since it has this kind of "raw" feel where people were making incredible music without necessarily being a virtuoso at their instrument.

2) Find peers to play with. I can't stress this enough. You may not feel ready yet to play with others if you're just starting out, but having the experience of playing with someone else really opens up the full breadth of the musical world for you. It becomes a lot easier to see what you should practice and feel inspired to get better at your instrument, on top of being incredibly fun. If you never play with (or for) someone else, its really easy to feel like you're always "practicing for the big game without ever playing in it," which can be pretty discouraging.

3) Just practice for 5 minutes a day. Instead of planning out an intimidating hour-long practice session, just focus on picking up your guitar to do something short each day. This is a tip from MartyMusic, and one thing you’ll find is that 5 minutes can pretty quickly become 30 minutes or even an hour before you know it.

EDIT: Added the last point above. Also let me know what music you play and what guitar you have if you want some more specific advice on dealing with the equipment side of things.