dear, I know your feeling exactly. The first relationship I have is last for 3 years also... I really treated as if he was my everything, and I can't imagine I lost him. But in the end I proposed the break up because I feel that our love is change, and I don't have the ability to make us anymore, although the decision to break up with him is so painful.
But after 1 month, he soon get a new girl friend... So I was wondering, did he really love me? 3 years can be substitute by 1 month! From that day on, I start to wake up, think clearly. It's lucky that I proposed the break up. Things started to change for some reason, maybe is not because of another girl, but sure there's some reason.
No matter what is the reason, insist on the decision you make. I know it's painful in the beginning, but I am pretty sure you sure can gone through it
A short pain is better than long pain!
P.S. I get my ex boyfriend back in less than 2 months. Find out how in http://www.lovetreatment.com