I read an article somewhere (and it related to The Bachelor show) by some professional person who said that it's not actually possible to be 'in love' with two people at the same time, or at least it's not possible to be in the same type of love with two people. The brain circuits have been mapped for various emotions and various types of love. Someone can certainly have physical feelings for any number of different people as there are many many circuits that are triggered for physical reactions. You don't even need the actual person there to have those circuits activated as just looking at a picture can cause people to become aroused and attracted. Smells and touch can get you going too, but the circuits that are involved in 'true love for one specific person' emotions have been researched and only one part of the brain is involved in that.
Now, who knows if Andy has reached the level of true love with any of these women that doctors have identified. Short of sitting him down with electrodes attached to his skull and hooked up to various machines and tracing his brainwaves as he interacts with each of them, we'll never know. But this particular doctor, based on her research experience, did think that Andy was experiencing lust emotions with Bevin and love emotions with Tessa. Hell, just as viewers we can see that Andy is experiencing lust with Bevin! Has he found true love? Stay tuned!