Regarding Felix, I truly believe he was a wonderful person, regardless of his excessive passions.
As to whether he was homosexual or not..., well the term has a lot of definitions. From all I've read (his bios, letters and so on), and from my personal experience and backround as someone who likes to try things(...), and has a degree in psychology too, I feel there clearly was a physical attraction from his part for men and for GD Dim in particular.
The question remains : did he ever get into a physical relationship? Well, considering his aristocratic selfishness (and I mean that with no disrespect),and to put it bluntly, I believe he got what he wanted everytime . In the case of the GD at least, I feel he was successful, as they loved eachother very much, and if the GD had refused him in ANY way, Felix's pride would not have standed it, and they wouldn't have remained friends after the GD was exiled.
Love comes in many forms and I feel he was "blessed with this curse", to quote a favorite author of mine. who are we to judge, after all??