Consider joining popular dating forums, meetup groups, and other online dating sites related to your niche

In general, if you are not going to publish a lot of content on your website regularly, for example, run a blog and update it from time to time, there is no point in investing your efforts in SEO. If you are planning to have a landing page with some basic information about your project and its concept, your chances to outrank multipage websites are pretty low due to the poor amount of keywords.