Both Stolas and Blitzø have romantic feelings for each other as well as their commonly-known sexual feelings. Because Blitzø has incredibly low self-esteem, he assumes that Stolas could never truly love him, and so only acts sexually with Stolas. But, because Blitzø assumes this and only acts in a sexual manner, this leads Stolas to assume that Blitzø doesn’t love him, and only desires him sexually. This also leads to Blitzø also believing that whenever Stolas is vulnerable with him, Stolas is just mocking him. Hope this helps anyone who was confused about the situation!