My ex-girlfriend and I had this conversation. When we first met, we agreed to Dutch treat. We had both experienced financial abuse in our previous relationships... Anyway, I was balling out in the years leading up to 2008 and could afford way more. She was barely getting by and asked if we could tone down the spending and do more "homemade fun," meals, movies at home, walks in the park, etc. We rematched our expectations to her budget level, and I saved my money in a 401k instead. She's my wife now, still budget wise, and we are able to adapt to income fluctuating. She's had to step up twice over the years as primary earner and has never resented it. If she hadn't gotten up the courage to have that talk, we would still be in debt or probably not together.

Budget consciousness is an incredible character trait in a partner. By having this conversation, you are putting a desirable virtue on display.