Potentially one of the most critical connections between sex and muscle building is the status within the body.
If a large break is taken for whatever reason, at first libido will increase, but over time if release is not achieved, levels may begin to drop.
This relaxation phase does not last for an extended period of time, however, and you will return to your usual hormonal levels in the body, but the take home message is that trying to attempt a training session immediately after you're involved in sexual activity may not be the best of approaches.