Getting deeply involved with someone during this transit will bring up all kinds of feelings that you will neither anticipate nor enjoy. The more intensely involved or committed that you get, the more old, unresolved feelings will start bubbling to the surface -- feelings of resentment that you'll direct at your honey, or urges to dominate and control their every move. What's supposed to be a sweet, loving connection will become troubled if you start feeling jealous or possessive.
If you feel that way, it won't be coming from a place of actual suspicion (or love), but from a place of wanting to control their every move. And the urge to control comes from feeling out of control, so take some time to inspect your feelings if this occurs. Does getting intimate with that special someone make you feel like your life is out of control -- like anything could happen at any moment? If so, it's understandable, because it's true. Anything could happen; that's why we should take our chances and live and love fully, without fear, without holding back. At the very least, remember that trying to dominate your sweetie is one of the best ways to end the relationship prematurely.