Giving away a free informational product such as an e-book, an email series or a mini course is a popular tactic many affiliate marketers use. Usually, your readers will have to provide their email addresses to receive the product from you. You can then use this to sell to them via email marketing. Additionally, an informational product can generate interest in the actual product you're trying to sell. If your product is popular enough and brings enough traffic to your site, you could also monetize the traffic in other ways, such as AdSense.
Another one of the highest paying and most popular dating affiliate programs is eHarmony, which is based on the actual earnings that can be made from each referred sale. Up to $188 can be made from a single sale. In general, the members at eHarmony are typically looking to find serious long term relationships, so many of them are willing to pay extra to find similar people.
Always disclose your affiliate relationship. Most visitors will probably understand that graphic ads will lead to your getting paid, but if you write a review or use an in-text link as a recommendation, you want your readers to know that may lead to compensation as well. This ensures you retain transparency and trust with your readers, but also, it's required by the FTC's endorsement rules.