Sin is “missing the mark”. If I learned nothing else while I was Eastern Orthodox Christian, it was that and how significant that is.
When you shoot a rocket to the moon, it doesn’t just get there. You have to make thousands of tiny course corrections otherwise you miss the moon.,
And that’s all sin is. Little misses that you correct as you go through life.
So, having love for someone isn’t sin.
But it’s possible that some activities are.
What would make cohabitation of two gay men who love each other difficult in a Christian context would be the temptation of having sex. But as celibate, being gay and loving each other wouldn’t matter. Love is love.