Bi-location
Liam won't actually be leaving you when he helps with the demon. SC's are never supposed to completely leave their charges. It's a rule. However, they can bi-locate. Liam can actually be in two places at once! Cool. Any way don't feel embarrassed that they never leave you. Certain situations, such as showering, bathroom area, "private time with DH", those kinds of things of "blocked" to them. They are there but they can't see or hear what you are doing so you can have some privacy. Nice how that works out huh?