You can both be reasonable and there still be a mismatch like this. Expecting something doesn't usually work. You're obviously reasonable in what you'd like, but it isn't happening. What you've tried hasn't worked. You need to try a different approach.

It's all about incentives. You need to analyze the incentives.

For example, when he was lying on the couch, and the house was a wreck, what was motivating him? Apparently the house being a wreck did not disturb him enough in that moment to choose cleaning over relaxing. If he was at all bothered by it, he's probably learned that if he does nothing, it eventually disturbs you enough where you do it. His incentives are all aligned to relax on the couch. It's a better deal for him.

You change his behavior by changing the incentives. You are in a living arrangement together. Love does not change the practicalities of how people are motivated, it is only another factor that drives them.

For example, if he could not expect for ignoring cleaning to result in it being cleaned, then he'd know if he's bothered by a mess, and he does not clean it, then he will continue to be bothered. If the mess accumulated, it would become more bothersome, and he'd be more likely to want to clean it.

There's many incentives. You need to understand his, and modify the arrangement. Until you can do that, trying to separate tasks based on the individuals is a temporary strategy. You can do things like set up a little trash bucket where you only put your personal waste, and you clean that one out, but leave the other one. Or align your own incentives so you too prefer to relax with him and accept the house being a wreck until you figure out a better system.