I think the main thing to be cautious of when you have an intense sexual interest (that many would refer to as a “type”) is that you may focus on the traits that excite you (a big dick, blond hair, dark skin) to the extent that you ignore the person they are attached to. It has little practical possibility of becoming a reality, and you aren’t really pursuing what practical possibility it does have (i.e., in the MMF threesomes that are difficult to set up and underwhelming to you, at any rate). In the realm of thoughts and fantasies, your interest in gay male sex is benign. When they become problems is when they manifest as potential harm to others, like in the case of someone determined to act out their abusive fantasies. Desires and fantasies are, for many of us, largely out of our control and, in their raw, immaterial form, innocuous. There is nothing positive about shaming a client for her desires, no matter how they deviate from the generic script of pro-social conduct pushed by supposedly well-intentioned people. It is chilling that someone who behaved that way has ostensibly devoted her life to service.
The scare quotes around “sex-positive” to describe that therapist are apt.
