I've seen 'The Ultimate Husband' pop up a lot when people are searching for completed romance or drama novels online, especially on sites that host web novels. From what I've gathered, the situation with a legal free download is pretty messy. There isn't a single official publisher that offers the entire novel as a free PDF or ePub for download. What you usually find are platforms that host the chapters serially, often with a 'read online for free' model that's supported by ads.
These sites operate in a gray area; they're not necessarily official, but they're not outright piracy hubs either. They'll have all the chapters, but you'll be clicking through a ton of ads and pop-ups. For a truly legal and free experience, your options are basically zero. Some apps might offer the first 50 chapters free to hook you, then require coins or a subscription to continue, which is a common tactic. So, no, a full, clean, legal download doesn't seem to exist. I ended up reading it on my phone browser during my commute, which was fine but far from ideal.