I have to agree. Fantasio's been seen to be attracted to girls too. I think it's more of a dislike of Secotine than a love for his Heterosexual Life-Partner Spirou.
That depends entirely on the writer;
some give Spirou a love interest others portray him as completely asexual,
some portray Fantasio as a (wannabe-)Casanova while others either portray him as slightly effeminated, gay or asexual.
The same with that heterosexual-lifepartners; in some stories Spirou and Fantasio live seperated in others they actually live in the same house.
In some stories the ho-yay is so blatant you could read them as a married couple in other they dont interact with each other so much, at all.
There are for example some 'Specials' written and drawn by different people. All of them have a different interpretation of them. In one of those stories one actually portrayed/ wanted to portray Fantasio as gay and pinning for Spirou in another Fantasio was heterosexual, again in another he cared for nothing more than his inventions.
I think that Fantasio is at least meterosexual. He likes girls, but he can't do anything without looking FABULOUS<3 and he's a total shopaholic in some volumes XD one of the artists actually think of him as gay :) dosen't make it more true, though...
and even if it's not canon, I still do ship Spirou and Fantasio just because they'r THIS frickin' close to go over from being Heterosexual Life-Partners to lover( they're just soooo tuchy feely with each other) and it's just soooo cute X3
lol I don't care XD blah blah blah blaaah yummylicious<3Really a case of Depending on the writer. Keep in mind the comic began in the sixties, where the moral code was very strict, to the point that it was more or less forbidden to draw attractive women (that's why Seccotine is so androgynous/tomboyish in her first appearances). Heterosexual Life Partners were the norm. Later reimaginings brought all sort of variations, with the main trend being Fantasio as a Casanova Wanabee and Spirou some kind of asexual. The latest books became more creative (especially the one shots), with Spirou occasionnally kissing girls or falling in love (he's implied to have sex with Seccotine, possibly for the first time, in a one shot), and Fantasio varying between womaniser and closet gay (the latest book have him tying Spirou's - admittedly old fashioned - tie).
Whatever your favourite work is, there is a Vocal Minority that considers it the Worst. Whatever. Ever!.

I've been reading Spirou and Fantasio comics these last couple of weeks, and in more recent albums it's not even subtle anymore.
Fantasio is acting like a jealous little biznatch whenever Spirou gets close to Seccotine, or any other woman for that matter. Spirou is all "whatever, we're just friends" to Fantasio, who is obviously following the guy around because he's genuinely interested in having a relationship with him.
Has this ever been openly stated, or confirmed, or is Fantasio stuck in a pristine glass closet?