Relationships today are tricky. People play too many games and carry too much baggage. You need every advantage you can get just to make it work out. That's why relationship information is also a very good subject to make money with. If you are knowledge about keeping a relationship strong or providing advice for improving relationships you might want to consider building a website for it. You can use adsense like this on your website to make money.
Or you can simply build affiliate websites that promote products that deliver dating advice. This is an affiliate website that I have which sells an e-book. The sign up is free. You have control over the amount you want to sell the e-book for. The listed price was $49 but I can't imagine charging that. I dropped the price all the way down to $14.99.