Hi there Stevie,
As @DickD said, I can relate to your story on many levels!
Its nuts that we both got diagnosed around the same time too and we both love video games and reading (well redditing for me)! I was diagnosed in May 2017 at 23 yo, I have had migraines ever since my teens maybe earlier. My migraines became progressively more frequent around the last few years leading up to my diagnosis. A year before diagnosis my condition began to rapidly decline: I had daily migraines, visual episodes (where I would become temporarily blinded on my RHS visual field in both eyes) that were thought to be migraine related even when they came without a migraine, my energy levels plumited, I couldn’t concentrate on anything.
This all took a big hit on my studies, I was in my fourth year of my MEng chemical engineering degree and this took a big toll on my mental health. I reached a point where after a 5 day lasting migraine, a week before my exams I refused to sit them, no medical evidence on my side. Doctors kept ignoring my concerns putting it down to stress and finally told me I probably needed an updated glasses prescription - I thought this was stupid since my specs worked just fine but went to the opticians. They found that I had lost part of my lower right visual field in both eyes. I was then sent to opthalmologist who confirmed this and sent me off for an MRI which confirmed I had an AVM.
My diagnosis allowed my university to confirm that I could defer my degree as long as I wanted. I moved back home with my parents in London and was sent for a angiogram. I was told I had a 4cm relatively high flow AVM with no signs of brain damage and that embolisation was the best choice with very little risk other than temporary sight loss due to swelling. Like for your case, this was incorrect.
The day of my surgery on 26 Jan 18 I was informed what I had been told was a misreading. There had been 2 national meetings to discuss my case due to the incredibly rare agressive nature of my AVM. I had brain damage due to how high flow my AVM was where it sat deeply nestled in the vision centre of my left occipital lobe. The vessels surrounding my AVM looked close to collapsing and It was imperative I had a intensive embolisation to close off as much as possible in one sitting. This would put me at a 5-8% chance of a stroke causing total RHS vision cut, RHS paralysis and loss of ability to communicate. Craniotomy would 100% cause total RHS vision loss and GK was too slow and unlikely to be successful with high risk of a fatal rupture whilst waiting for it to work.
I went through with the embolsation since I didn’t really have much other choice. I had a 7.5hr surgery as opposed to maximum 3 hrs we were told it’d be. I had a stroke during my op and as a result lost the majority of my RHS vision in both eyes. Luckily I still have my central vision intact and a little upper right vision too. I was informed why though… they closed up 3cm but left 1cm left - which is located on the part that controls central vision which they didn’t touch. They sucessfully lowered the blood flow to the AVM giving time to decide what to do with the remaining AVM which is higher risk of treatment than my last op.
You can see my development in vision in this post link: My sight development (post embo occipital AVM)
With my sight as it is since I still have central vision I can read, go out independantly unaided (though I do bump into things/people sometimes). I am now terrible at finding things as a result and can’t drive which is a real bummer as an engineer but it is what it is.
Like you I live with the fear of losing my remaining vision and independance. I think what helped me alot is going to cognitive behavioural therapy which helped me cope better - I completed my sessions preop but what I learnt is still helpful now.
In terms of relationships, I’ve learnt alot. Unfortunately my boyfriend wasn’t very supportive and made me feel like a burden. I broke up with him a month before my op because the emotional stress got too much. I realised alot:
- I survived a stroke without him and despite thinking I couldn’t do it without him: well I did and proved to myself I’m stronger than I thought
- even if I do have new baggage , there is so much more to be than this AVM stuff, I am worthy of being loved and supported because I am a great partner too.
My point is, you are not a burden and never will be. Whether or not he sticks around if in the hypothetical future you lost your vision, you will be fine either way. From the sound of your post you are a caring and loving individual - if it was the other way around you would support him too. You are both lucky to have one another.
I am now certified partially sighted, as a result of the radiation during the op I have lost half of my hair (if you wanna see baldie pics My left occipital embolisation story), I have gained a fair bit of weight after spending nearly 2 years not moving around much and I might be blind in the future - but you know what? I have realised I am still more than worth it and so are you!
I recommend spreading out your support system if you havent already and keep coming to us too so you don’t just load it onto any one person. Also CBT or counselling so you have an hour week just for you to talk and be 100% open about your thoughts and feelings. Also honestly right now is the best excuse for guilt free TLC - try to fit in time to do things that make you feel good. TLC for me for example is getting my nails done at the salon, improving my diet to work on my figure, some retail “therapy”. I also have been loving watching the daredevil series on Netflix, seeing a blind superhero gives a more positive perspective - I am just now waiting for my own super powers to show 
Sorry about this all being so long! Welcome to PM me to chat or vent whenever 
Lots of Love,
Corrine