Can someone see my internet history if I use their wifi?

Contrary to a common misconception, the network key is not the encryption key. The WiFi communication is encrypted on its own using a key exchange protocol. This makes it impossible for anyone without abnormally huge processing power to decrypt anything that goes through. That said, the answer to your question - Can someone see my internet history if I use their wifi is that if the person controls the router, that changes things as the router can see everything that goes to the Internet which is not encrypted. The router can see..

everything you send and receive that is not encrypted including documents, pictures, URLs, emails most hosts that you visit even if using HTTPS because of its DNS server which allows the hacker to match the IPs with the hostname even if the HTTPS protocol can hide it the type of things you do based on certain factors like the port number, bandwidth used in both directions, and session duration Some would tell you that you might want to use a VPN to hide most stuff from the wifi router's owner, but you would then put it in the hands of a total stranger which is not better.Real solutions include (and may combine):

Using secured connections for everything you prefer to keep private. Getting your own Internet connection, therefore being free from the undesirable watchdog. So, based on all that, Wifi peers are of very limited risk of knowing more than the bandwidth patterns which may be spied on. The only people who really have access to spy on what you do are upwards in the network, starting with the Wifi router's owner which could see everything that I mentioned can be visible. Any other equipment on the network path followed by each of your connections can see the same kind of things in their context which is typically limited to one (or very few) connections you do. The closer they are to you, the more they can see, which means that your ISP would see almost everything that your Wifi router's owner would.