Alright. If I understand the query properly, we are discussing the sociological impact of being upfront with a partner about sexual history and how that may impact future relationship dynamics between the two parties. The first things I would work on in anything related to social science research are the operational definitions for the variables in question. In other words, what do we specifically mean by disclosure? Is it how many partners they have had in the past, or does it refer to a disclosure of a specific partner? This will largely determine what the second corresponding variable is. For now let's assume we mean actual number of partners.
The second operational definition that needs to be addressed would be what we mean by healthier lifestyle. Is this a general improvement or something specific? Make sure that you address what the actual thing that is improving is; otherwise, you can't show a positive correlation between your two variables. For now, let's say that the second variable is openness in the relationship. Again, be certain to define exactly what that looks like.
So the line could read: "If both partners disclose how many sexual partners they have had to one another, then this could lead to an improvement in overall openness in the relationship, such as feeling more open to honest dialogue between the couple on a multitude of issues."