So darn easy
The problem is, I think, we are so conditioned to think that people feel the same way we do. If a guy goes out of his way to be in romantic situations with me, I assume he is interested in me romantically.
This is what the predators - not only bi-sexual - do. They are so very careful to manipulate you, using your desires and expectations. They know exactly what they are doing. When you then tell them what you feel, wham! You get the whole "I never said I love you, I never said this was anything but sex" routine. They make it sound like it is all your fault. And then they get all huffy about it.
There is absolutely nothing wrong with just having sex. But you need to be absolutely honest about it - and not saying anything is, in this case, very much manipulating and lying.
If I am interested enough in a man to want to have sex with him (I gave up causal sex for fun sex a long time ago) then I say so. If he fires right back: just sex, nothing else - well, then the ball is in my court. But if he says, yeah - he wants to get to know me too, build a relationship and so on...and it is just bullshit to seduce and use me, then I am entitled to feel hurt, used and angry. Oh, relationships can end because your are incompatible. That is ok. But to lie and pretend as so many men do, well, they are despicable.
Rule of thumb: Men who are married - whether to women or to another man and have sex with the same guy more than once without being absolutely clear about what they want are leading you on. They are predators and will hurt you - then tell you it is your own fault.