Here's what American Psychology Association ethics code has to say about potential multiple relationships:
"3.05 Multiple Relationships
(a) A multiple relationship occurs when a psychologist is in a professional role with a person and (1) at the same time is in another role with the same person, (2) at the same time is in a relationship with a person closely associated with or related to the person with whom the psychologist has the professional relationship, or (3) promises to enter into another relationship in the future with the person or a person closely associated with or related to the person.
A psychologist refrains from entering into a multiple relationship if the multiple relationship could reasonably be expected to impair the psychologist's objectivity, competence, or effectiveness in performing his or her functions as a psychologist, or otherwise risks exploitation or harm to the person with whom the professional relationship exists.
Multiple relationships that would not reasonably be expected to cause impairment or risk exploitation or harm are not unethical."
It's a appropriately vague. I honestly like the American Counseling Association's code of ethics in terms of this just because it's much more explicit about what to do and more helpful in terms of potential liability and documentation.
"A.5.d. Potentially Beneficial Interactions
When a counselor–client nonprofessional interaction with a client or former client may be potentially beneficial to the client or former client, the counselor must document in case records, prior to the interaction (when feasible), the rationale for such an interaction, the potential benefit, and anticipated consequences for the client or former client and other individuals significantly involved with the client or former client. Such interactions should be initiated with appropriate client consent. Where unintentional harm occurs to the client or former client, or to an individual significantly involved with the client or former client, due to the nonprofessional interaction, the counselor must show evidence of an attempt to remedy such harm. Examples of potentially beneficial interactions include, but are not limited to, attending a formal ceremony (e.g., a wedding/commitment ceremony or graduation); purchasing a service or product provided by a client or former client (excepting unrestricted bartering); hospital visits to an ill family member; mutual membership in a professional association, organization, or community."
In the end it's up to the psychologist/therapist depending on his/her comfort level with the code of ethics. You could ask him/her about it, but previous posters are correct about the ethics codes established for safety issues due to the tremendous amount of trust therapists are given. I'm not saying for or against, but it's something to think about.