What you do together is life. What you think about doing together is imagination. Bringing those to ideas together into all the things you like to do, anticipate doing in the near future, and aspire to do as part of your long-term goals... All of this is part of building and nurturing a relationship for the future.
Keep sex out of the game until you are sure you want to give this relationship a long-term shot. Sex clouds everything. Sex blinds us to the red flags that could be burning right before our eyes. When the sex hormones kick in we are no longer capable of making rational decisions.
Over time, as adults, we develop coping mechanisms, strategies, action plans, for dealing with our own shit. Either we get pretty good at it, or we don't. When we're not very good at maintaining our own emotional boundaries, things begin to come out sideways.