In Treatment Melissa George

I think that this situation is very possible.  To some people, their therapist is the only place they turn to, the only person they talk to, and this can be very appealing to someone.  Someone may feel that if they have already shared all their deepest and darkest secrets, they have nothing to hide, they feel so comfortable, that they start to love and want their therapist to be closer for them. 

I was only treated by female psychologist and I never fall for any of them (I guess the fact that they were all above the age of 50 also had something to do with it...) but this is a very known symptoms in psychology, I think it's called disposition - when the patient develop strong emotions toward the therapist, mixing up professional support and friendly support.

I think Freud mentioned it a few times claiming that to a degree it will happened in every therapeutic process. A part of his approach to the roal of the therapist (remote, uninvolved and so on) came from not wanting to encourage emotional dependency in the patient. 

I can totally see it happens, I think that the main reason for it is trying to avoid the real difficulty of opening your hard to a stranger and dealing with one's own problem in forming relationships and so you turn the therapeutic process to yet another relationship - It's very damaging to therapy, and yet it happens all the time. 

I have heard of persons who felt in love with their therapist, but that really helped them to get across their diseases. Actually, my brother felt in love with his therapist during his ambien detox.