hey, well i think 3 years of a relation is long enough to build up a level of trust right? If you've been dating him for 3 years, theres no doubt you've had your ups and downs, but I'm sure through it all, you've gained each other's trust right? Well when he tell you yours the best thing in the world, hun, believe him. I'm a guy and I can see why he would sometimes glance at others girls...we can't help it. But you have to understand that just because he looks, doesnt mean he wants them more then you, or will cheat on you. You can't expect him to be a robot and not look at any other girl again. Als how old are you? Feeling so jealous, no matter how long u've been dating, would also have to do with all the hormones in your body. Overtime your jealousy will faid, and you'll realize that he loves you with all his heart, no matter how many girls he looks at. Don't worry about changing yourself to suit his liking, you ARE who he likes, from day 1 you were.
Hope I helped
