Hi, the signs of jealousy are pretty horrible to be honest. If its you feeling jealous then it will affect your body in various ways. To start with the shock of seeing someone you love for example, with someone else can make you hyperventilate, breath too quickly, and you can pass out. Your hands feel clammy and cold, and you break out into a sweat. Your stomach feels as though its in knots, and the fight and flight mechanism of your body kicks in. You want to run away and hide. It can also make you get really angry very quickly and the burst of adrenaline will pump blood to your muscles making you feel strong. you feel that you want to hit the person, but by taking deep breaths you can calm down and hopefully walk away.
If you think someone else is jealous the signs are there in the above comment. Their face will go very red, then change white within seconds, Their movements will become stilted and they won't know how to talk to you or the person they are jealous of. Not a pleasant thing i must add!
One last point, no you can't love without jealousy, I don't believe its possible. to love means that you feel the bad stuff as well as the good.