Final answer:
To manage increased stress from relationship pressure, the client should use assertiveness techniques to clearly communicate her feelings and boundaries.
Step-by-step explanation:
A client experiencing increased stress due to pressure from her significant other to move in together should consider using assertiveness techniques to address her situation. Assertiveness involves communicating one's feelings, needs, and boundaries in a clear and respectful manner, which helps in managing stress caused by interpersonal relationships. This approach enables the client to maintain control over her decisions and life situation while effectively communicating with her partner about her readiness for such a step.