"I love him to pieces but he treats me like something he's trodden in that is stuck to the bottom of his shoe."
Is that about the size of it?
Actions speak louder than words.
Yes it is normal for the honeymoon period to wear off 6 months to 24 months into a relationship.
At that stage, all the good points of the partner get taken for granted and focus is shifted to all the bad points.
There's a high chance that if you look back things, you'd see that the warning were there as to what he'd turn out like. For example, the way he speaks to his mum and dad, that will probably be how he speaks to you now.
It's the oldest mistake in the book to stay with someone in the hope that they will change for the better.
Trying to change your romantic partner is also a mistake. Influence them, yes. But don't try to change them. Either accept and tolerate them as they are, or get out of the relationship.
He seems to be hopeless at long term relationships.
The longer a relationship goes on, the more important it is to go on lovey dovey dates, or week-ends or holidays away.
The longer a relationship goes on, the more important it is to regard it as a partnership, with you giving your partner almost as much love and affection as you give yourself.
Any relationship of any duration should be built on win wins. It sounds like he's poor at creating win wins with you?
Please feel free to tell us about any outstandingly good features that he has.
If he is outstanding in one or more areas, it might be worth you sticking with him, and developing your own self-esteem and self-approval, as an armour for his emotional coldness.
If he's just a fairly ordinary, run of the mill guy, you should dump him, enjoy your freedom as a single person, and start your search for a new boyfriend.