Can you do a different trip with just her, or even a couple smaller more inexpensive over-night trips?

Your OP makes it sound like you're planning on going to multiple events. Is it just Veld, or can you do Veld, one rave, and a mud-run, one of the parties but skip another boat party to go on a day trip with her (or whatever combo works for you)?

Surely you find ways to "mini-vacation" alone with her around these events or even day trips? Seriously those can be really cheap. A day of hiking, an airbnb or camping, etc. Even if you missed a day of one of these many festivals you mention (totally doable) that would give you enough time off to make a special one night vacation for her (not Veld of course, since that's only two days, but another one). If you can't even afford a night in a motel or tent you really shouldn't be collectively dropping $800 ($400 each) on one festival right now. Can you go to Toronto a day before your friends get there and spend a night in a nicer place/ have a nice dinner. Can you cut costs elsewhere during the festival (i.e. drink and consume less)? Personally, I go to a lot of festivals and stuff like you are describing, but I also get exhausted by all of it over time and anxious (I'm more an introvert). I also find more intimate vacations really meaningful for my relationship. With my current partner/ at my current age it's not a big deal to pay for and take time off for both. However, when I was around your age my partner and I would have to find a compromise. So we went on some really cheap vacations that didn't require time off from work at all (or if they did only required a half day). Some of my favorite memories really are as small as brunch in bed at our home, a short drive to a campsite, window shopping in a little beach town, dinner and a night in a $40 seedy motel drinking boxed wine and watching bad television (unless you both work 7 days a week, this is completely doable). Book something small for her like one weekend a month and phrase it as "I want to take smaller vacations this year. Instead of one big trip, we can take two mini-vacations. One to the festival and one to the beach, lake, mountain or wherever. We still can't afford Ottawa for a week, but we can definitely do a Saturday night camping on the coast and another weekend in September at an airbnb in a nearby city."

I also get exhausted by the festival scene. So for a four day camping festival we once drove down to the area near the festival the night before and spent a more "romantic" night in a motel and had a nice brunch together/ did some sightseeing as a couple. Then we joined our friends to set up camp at the start of the festival. I bet she'd appreciate you researching the area/ finding something inexpensive to do on either the way back. It'll be just to two of you and feel more special. Same with a smaller weekend or overnight trip. Skip a few of your friend events (though not all) and save that money to take her on one small overnight vacation. You don't have to go to every rave, festival, boat-party, and mud-run, but you can still pick one of each of these and have plenty of free weekends and more money over the summer for smaller things.

I don't understand how you are saying you can either afford Veld (which is seriously 2 days long on a weekend) or a week in Ottawa? If you can take a week off for Ottawa surely you can take a day or two off prior to Veld and combine a vacation in Toronto or nearby areas for two days with her and then the festival. Seriously pack food and get a cheap place to stay. Get to Veld a few days earlier than your friends. You'll have a much better time because you won't be at a hectic and chaotic festival resenting each other.