YAI is a agency out of New York that has a relationship video series I really like. They also have developed a determining sexual consent manual (which you can get through their online resource center).
Unfortunately, this is not a free service, but as far as somethings go, it’s not too bad. For $150 a year you can buy membership to the YAI’s online resource center. You then get to download tons of materials. They have a lot on relationships and sexuality. Some of it is geared toward staff/educator preparedness but they also have lesson plans. Many of the items are available to purchase separately without buying membership to the resource center (and other items, like the relationship videos, aren’t available to download).
You can check out some of the resources available during a free trial.