Most Helpful Guy
Cut him off or pull waaaayyyy back on the (physical not emotional) reigns and see how he reacts. If he bounces or suddenly loses the majority of interest, you have your answer.
*Side note: a lot of this can be avoided if you were to say make him work for any form of physical intimacy. Make a rule for YOURSELF, no intimacy until at LEAST 6 months of steady monogamous dating. In general, this will weed out about 95% of the guys that you DONT want to date let alone be rewarded with the kitty.