What are the renovations that cost almost $400K? Are they necessary to get the apartments ready to rent? Is your partner contributing to any of this, or is it all on you financially?
You feel stuck because you are. You don't have a million-dollar house, you have a $1.4M house on a $200K salary. That's a lot, and it brings a lot of stress with it. You literally cannot afford to quit because of your financial obligations on the house. And there's nothing like feeling stuck in a job to make you really, really hate it.
So what changes are you willing to make? If you want to keep the house, that means staying in this job, or finding another equally high-paid one. Is that worth it? Are there other high-pay jobs out there that you might be interested in? Where would you live if you sold the house? Are you interested in rental properties in general, or was that just a bonus that made this house feel more affordable?
The immediate thing that you can do to lighten the load is to focus all your time and energy on getting the apartments rented. That's not a cure-all, as your best-case scenario still leaves you with $3K in mortgage + another $3K in personal spending (not counting ongoing maintenance/repairs/vacancies), but it does cut the net mortgage down to a more manageable number that can give you some breathing room. Even if you average out to net costs of $84K ($7K/mo), that's a lot better than $120K ($10K/mo).
Where is your partner in all of this? I know you have separate finances, but what do they contribute to the housing costs and other monthly expenses? Do you think this is a permanent situation, or are things somewhat iffy? What are your partner's long-term goals -- where do they see life in another 10 years, and how do they propose to get there? It seems like you are shouldering a huge amount of expenses on what would otherwise be a very generous salary, which is creating a ton of stress for you. What is your partner willing to compromise on to ease your load?