I don’t know if I fully agree with this quote. I’ve had long term relationships where I truly loved the person and did much for them yet they didn’t feel I said enough reassuring things or was intimate enough which made them question my feeling when they couldn’t have been more wrong. I feel like the significant others personality and insecurity plays a huge role. You can say/feel/act/etc to your hearts extent or what you feel was the most you could give and it may still not be enough for the other person. So if someone feels like they aren’t getting what they deserve it’s not necessarily your fault, they might have too high of expectations, too low of self esteem, or maybe simply ungrateful/greedy. Just my two cents from my experiences.