Okay, this is a difficult question… 
On the one hand, real people can actually be romantically attracted to people they’re not sexually attracted to. For example, I’m very similar to your character, as although I’m only sexually attracted to other guys (and nb people), my first romantic crush was on a woman.
On the other hand, presenting a character as homosexual and then letting opposite-gender characters romance them can feel… well, I wouldn’t go as far as homophobic, but it can feel invalidating. It doesn’t help that it can tie into the legitimately homophobic narrative that "the right girl can cure you", which I’m sure is not your intention.
And this is one of the problems with trying to accurately represent reality: it’s not neat, and it doesn’t make good stories. And trying to fit it to stories will end up simplifying it in unintended (and potentially harmful) ways, especially if you’re talking about minorities.
In your case, it would probably be for the best to present the character as bisexual but with a preference for the same gender. This probably wouldn’t require much rewriting at all, but would avoid the potential harm caused by presenting a character as gay and then appearing to allow female MCs to “cure” him.