The phenomena of fusion within a lesbian relationship is described in a six-phased model. Fusion in relationships is defined as two incomplete people coming together in an attempt to make one more complete whole, the merging of two ego boundaries. The six phases discussed include ecstacy, getting married, the routine, depression/withdrawal, pulling apart/conflict, and ecstacy, again. Attention is focused on clinical considerations and therapeutic interventions. There is discussion of norms within the lesbian subculture that reinforce unhealthy patterns, diagnostic concerns, special treatment concerns when working with gay clients' and innovative treatment strategies. Clinical case examples highlighting both the dysfunctional aspects of these relationships as well as the potential for healthy outcomes for the women and/or the relationship are discussed. The paper contends that approaching the treatment with certain assumptions of health and potential for growth may allow many couples to have the opportunity to flourish individually while remaining with their lover. It concludes that, regardless of how long a couple remains in treatment, the therapist has an important opportunity to educate the women about their potential for mental health. (ABL)