Gypsy-dono

so in a lot of romance manga (that are more specifically school life/slice of life/romance/shounen and shoujo) you have rivals correct? most common rivals would be normal rivals like guy (a-kun) likes girl (b-chan) and the rival is another guy (c-kun).
well i recently got to thinking whatever happened to gay rivals (like a-kun loves b-chan and c-chan loves b-chan) and they aren't like secondary characters im talking main rivals where they are portrayed as true rivals to the protagonist. i can't say i read visual novels or lots of manga but i have followed lots of school life romance manga and i rarely see the lesbian/gay rival as part of the main characters. why is that? i can understand some people are uncomfortable with that kinda thing but i mean it seems like a very rare theme in romance manga. i know some manga out there like

Venus In Love
http://vatoto.com/comic/_/comics/venus-in-love-r5135

and don't get me wrong im not talking about yuri/yaoi and shoujo/shounen ai. talking strictly shoujo and shounen and seinen. i find it weird its not a huge cliche.

I don't get it. i just can't come to like general josei artwork. i think its cause of how realistic it looks but idk. i've stuck with shoujo and shounen only because i just cant like josei artwork. there are a very few where i read them not cause the artwork was nice but because the plots were amazing. i feel like this is a huge fault of mine tbh and i wanna know everyones opinions about general josei artwork. i feel like if i can come to like josei artwork my reading horizon would broaden phenomenally.