My family always thought I was "pet crazy" and "had too many", which turned out to mean anything more than 1 pet total. Over the years I've accepted how they feel, but it doesn't mean I have to like it or give it any additional thought. I don't live with my parents anymore, and my house is always clean when they visit so they don't really have much of a say in my home life.
As far as pet bills; I keep the number of pets I have limited so in an emergency I have the funds to spend. For instance if I fell in love with another, say, rabbit tomorrow, no matter how attached I get I personally consider "Do I have the funds in my account right now to take this cute fella to the vet in the next 48 hours if necessary?" It goes from there.
My dog Troy broke his leg 3 or 4 years ago doing agility. He shattered his back leg spirally. Start to finish that leg cost me $12,000. Would I spend it again? Yeah.
Would I spend that to save any of my rabbit's lives if they broke their leg, etc? Yeah. But it comes down to quality of life. Troy had a good prognosis of being able to use his leg again. If one of my bun's shattered a leg and it was a very small chance of using it, I'd probably have the leg taken off instead, or get a bunny wheel chair.
If I look into my pet's eyes and see that fight and want to go on, yeah I'd spend it. It's just money. When I'm old and gray and thinking back on my life I hope to god I don't think about money I've "lost" or "wasted" but the friendships I've gained through my beloved pets.