Yes, according to some accounts, Poseidon had at least one male lover.
The most well-known male figure associated with Poseidon romantically is Nerites. According to ancient sources, Nerites was a beautiful sea deity (sometimes described as a youth) who was loved by Poseidon. The reference states that the mutual love between Poseidon and Nerites is even cited as the cause for Anteros' birth, who is the God of requited love.
While specific details about their relationship are scarce and vary across different sources, the existence of Nerites as a male figure romantically linked to Poseidon suggests that Poseidon did have male lovers, or at least a significant same-sex attraction. The significant age gap does raise concerns, however.
