Performing a local network man-in-the-middle (MitM) attack is fairly straightforward, especially when the traffic is unencrypted HTTP. There are other approaches to encrypted SSL/TLS HTTPS connections, such as using SSLStripper.
My question is, provided I own the HTTP certificate, for example to my own website, how could I MitM clients on my network to read their traffic? I would assume that since I own the certificate then decryption would be straight forward, unless they are using a VPN or similar privacy enhancing technology.
This could either be decrypted on the fly, or saved so I can decrypt it at a later date, either approach is fine.
EDIT: Assume I own the private key, sorry for ambiguity.