Your father can retaliate against you for talking about it with the therapist or anyone else and can make your situation worse. If this was reported to authorities like police, it's unlikely that he'd do it because that would get him into a more trouble. But a therapist is not a legal authority.

I generally would not trust a therapist who implied that my sitting position may contribute to my father sexually abusing me. As I said, I don't know if that's exactly what your therapist was implying, but if I were a client and had a feeling that she did, that would be enough for me not to talk to her any more and to look for a new therapist.

As I said, I don't think your therapist is doing a good work with you, but I think so for the reasons slightly different from what others suggest.

I think too that she should not be talking to anyone in your family. It's not her job to investigate what's really going on. She has to work with whatever you tell her and not to go beyond that. She should have enough expertise to know how to navigate this situation best without bringing outside parties into it, which does NOT navigate it best.

I don't think she is "implanting" the idea that you are being abused. It is a fact that you have reported here and to her. The way your father is touching you now IS abuse, and that is a fact, there is nothing there to "implant". In regards to the past, I too can say that it is very likely that your father abused you since you were a child, because I have not seen any case when sexual abuse of a child came out of the blue in their adulthood when everything was fine before. It just doesn't make sense that a healthy parent with a normal protective parental instinct who has always behaved like a healthy parent, all of a sudden got an idea of touching their child inappropriately when they grew up. Once you are bonded with the child as a parent normally does, that bond never goes away no matter how old the child is. They are always your baby and you never look at them as a member of the opposite sex that you can have a different relationship with. As a normal parent I know that and any normal parent on this board knows that too, I am sure.