First I just want to say, just as long as there are men & women in this world the dating niche will always be profitable. So yes it is a good niche.
If you built into this niche, how are you going to attract users to it?
Now, this is a question that everyone should ask themselves before starting their business. That's a really good question Harry P. A lot of businesses fail because they build a business without asking themselves this important question.
The answer to your question is really simple. Where do people in the dating niche hangout?
If you can answer that then great stuff, you're on the right track but if you can't answer this question then the best way is to do some serious research.
There's a lot of ways to find out where people in a specific niche hangout. One way is to analyze other websites and blogs in that niche. Study them then come up with a way to tap into their traffic source(s). You can also search for discussion boards, groups (google plus, facebook, skype etc.), reddit, forums or any type of online community.
There's no one way to get traffic for all niches, different niches require different traffic generation strategies. For instance, one thing I would check to determine if I want to go the SEO or social media marketing route is to check the engagement on other dating sites.
If the blogs/website get a good number of comments, shares and good engagement on social media sites then what you have to do is to find out what type of content their audience reshare/retweet the most. This will help you start your marketing campaign with content that is worth sharing then you grow from there.
If there's less engagement on social media for your niche and you choose the SEO route, my advise is: Be Careful, SEO is not free (yes I said it) and it's not cheap either. If you spend anything from $300+ then I can say you're doing SEO, less than that might work for some niches but these days that's rare unless if your goal is to get 1 visitor per week from search engines.
Anyone who wants to argue my point, make sure you bring concrete evidence, no assumptions. I don't want to see the rankings, I want to see the traffic (number of daily visitors) and the sales you're getting with cheap SEO. Why, because people will show off their rankings that are not bringing any sales, just to look cool.
Also check out this article, it might help as well:
https://www.webmastersun.com/threads/12368-Blogging-Your-Way-To-Success-In-2016
Good luck Harry