.... so will see if I can use potential offers to force an increase in my wage that way. Cheers for the advice guys
I feel I ought to issue a word of caution here.
I'm not suggesting, quite, to use a job offer as a form of blackmail. Or if you do, be very careful how you do it. Be aware, in my opinion you have to commit to going and taking the new job, not just using it as leverage.
It's all in how you present it. To put it in cartoon form, if you roll up to your boss and tell him you've got a better offer and he'd better match it or you're outta here, you'll probably get marching orders. Or worse, he'll agree, match it, wait until your offer has expired then quietly recruit your replacement before finding an excuse to dump you.
On the other hand, if you find the new job and then hand in your notice, clearly very reluctantly, pointing out that you love it there and hate to leave but you're finding it increasingly difficult to manage and, after all, haven't had a rise in three years .... I'm sure you get the picture.
This whole business is a game, and he looks to be playing it. You need to, as well, but play it smartly. Think, don't react emotionally.
If you'd like to stay, then play it with that in mind but bear in mind to do it properly, handing in your notice has to be sincere because he might not try to talk you out of it. If you try this, you certainly do risk burning bridges, so only do that if you really are willing to jump ship if it comes to it.