Haha, I remember when that started being spread around. While I've got no problem with the possibility that he might be homosexual, I always viewed him more like a samurai: dedicating his life to becoming stronger and mastering his craft. He travels with those close to him, but is probably platonic with everyone. His relationship with Ranulf and Soren always felt more like that than anything. Ike's goals and motivations don't really fit with having a romantic relationship. His support conversations with Soren are fantastic though, and his final conversation with Soren at the end of RD is especially touching. People say that Ike's boring and devoid of emotion, but that conversation is a great example that he's pretty complex.
I always liked Ike and the tellius games for this reason: they avoided the "oh here's a female just for a love interest" trope. That's why characters like Elincia and Titania worked so well, there was no pressure for them to be love interests, they were just good characters that stood on their own.
Although, I guess he got it on with someone given that he's got a descendant in awakening!