My unpopular hack is being single.
Hear me out.
I feel in a relationship or marriage there's always so much pressure to do 'activities' - meals out, nights out, weekends away, presents... You basically push each other to spend. My friends' grocery budget is 1K a month for a couple!
Being single, my grocery budget is negligible, I eat very simply, no treats. I don't eat out or do weekends away as I actually don't enjoy this.
Occasionally I date and it always makes a huge dent in my budget, endless outings, drinks, Sunday roasts and pub lunches I actually don't want.
Being single, I do the things I don't really care about on a shoestring without having to justify myself, and spend money where I genuinely want to.
I feel that in a relationship you do the things you want to do for yourself, and then also spend money on things required to compromise with the other person.
Dated a guy recently that had no money and very little interest in it, so our dates would be just sunbathing in the park and chatting, walking around the city and chatting, or cooking normal food at home. Gave me a totally different view on finances in dating and relationships.
My single finances are so much stronger than what they used to be in a relationship, and so are my XDP's.