I just read this thread title again. "what sign do you prefer to date/ get involve with?"
The real question is, who are we dating and who are we "getting involved with." At the end of the day, I wonder if there is really a difference... I think most people with a very heavy Scorpio influence are unable to remain detached. Scorpios are all or nothing - they either completely fixate on you or you don't exist. So "getting involved with" someone, even with the most innocuous of intentions, will probably end in disaster.
I know I can never be a "casual" person when it comes to love. We love and feel so deeply! Once I tried to remain completely detached - that failed miserably.
I have a Scorpio stellium: Moon, Mercury, Venus, Pluto all in conjunction
(And yet, most people still somehow think I'm an Aries)