To be honest I feel embarrassed/awkward asking for something that is part of a normal sexual relationship.
Just do it. You are in the right- this is normal.
Another thing I've found is in the last few years more men seem to think that jabbing their fingers at the vagina does something. The 'G spot' thing maybe works slightly for me if they get at the clit at the same time, but otherwise no.
I have discussed it in the past.
What happened when/after you discussed it? Did he improve for a bit and then slack off again? So, he knows what you need, he just can't be arsed.
I should also add, he does take things to heart and I think he would see this as me being critical, I’ve addressed things with him before (not sex related!) and it doesn’t change, or it’s not taken on board constructively. If I address this and it doesn’t change, do I then accept how things are?
No, you dump him. Surely you don't want to accept that this is your life now- this is your sex life, for life?
And also that he doesn't compromise/change after discussions can't make for a good relationship.
Yes, you are giving a criticism, though you may not phrase it that way, and one he richly deserves. A decent guy a) wouldn'tve been like this in the first place, and especially after you've already mentioned it to him, or b) if you mention it he takes it on the chin, apologises, and gets his finger out.