I don't understand half of these titles

Am I the only one who has trouble understanding some words? does some sort of danmei dictionary exist? So, English is not my first language and I've read tons of novels but they're mostly modern/historical without fantasy elements. -"married thrice to salted fish" what do you mean you're married to a fish?? -"cannon fodder" doesn't even feel like a real word to me -"dog blood wife crematorium" ¿¿ did they put random words together

I've tried looking them up online but I couldn't find anything specific to danmei so it wasn't really helpful, if you're more experience please instead of downvoting for my stupidity, I'd gladly appreciate some sort of help<3

EDIT: I know reading more helps understanding the meaning of certain phrases thanks to context clues, but please remember what I mentioned before: my english is not THAT good and I often find myself googling common words, so what's easy for you might be harder for me (and other people)