THE FACT THAT HE IS TRYING (which I've seen all along) is a MAJOR FACT.
Perhaps its time you took him aside and said to him: "H, I'm trying too. It seems we're both trying in the wrong ways. How can we correct this?"
Then open your ears and LISTEN without trying to defend yourself. Take out a peace of paper and split it into two columns. Tell him, "Let's see where we are going wrong here, OK? How are you trying?" -- then write down everything he says in his column without judging him. Hand over the pen and paper to him and share with him how you are trying. Then take each point and dissect it. Share with him how each thing is trying is not working and offer an alternative to it. And you do the same.
NO ANGER, NO HURT, NO RESENTMENT. Talk like two adults.
G I'll respectfully disagree, this is how most WAS's start talking just before getting ready to leave and just before starting affairs - it's the arrogant, cocky, getting ready to leave attitude, the look in their faces when they say certain things, the attitude that you'll be losing and they'll be gaining by leaving, etc.
Saying "I'll always love you" isnt the same as "I love you too", it's usually a prelude to saying "I love you but I'm not in love with you"