In your OP, you say that you have shown him how to give you pleasure with his hand, but that he gets "bored" if it takes a while and that he "loses a lot of his erection".
I just wonder if "bored" is the right word.
Could it be possible that he associates pleasuring you by hand, especially if it takes a while with losing "a lot of his erection". As you know, the self-fulfilling prophecy comes into play.
I am coming more and more to the view that the majority of problems in the bedroom come from fear on the part of the man of losing (or worse, not gaining) an erection.
While there are undoubtedly selfish men out there, I am less and less comfortable with the broadbrush concept of the generality of men being selfish in bed.
Some wise person once said that you can criticise most men about anything except their driving and their prowess in the sack.
The age of your DH is not clear from your OP - but the reality is that once he has peaked at eighteen or whatever, he is on a slippery slope performance-wise. A few hiccups and all kind of avoidance behaviours can start kicking into play.
I just pose the question - but is there any danger that your quest for your own orgasm (totally natural) has left your DH slightly unattended? (In posing the question, I am not looking for a specific answer from between the sheets).
But could I suggest that as each year passes, your DH will need more and more "attention". Erections do not just stand up looking at you without attention - and each birthday makes such a happening more and more of a distant memory.
Would you feel it possible that man with fully attended erection is very unlikely to get "bored". None of this is to take from your desire for your own orgasm - but there are two of you in the bed (or wherever).
At least you are not giving up on seeking an orgasm-filled life, but perhaps if you could put the focus on both of you rather than solely on your individual orgasm, the journey will be more pleasurable for both of you.
On a practical note, if you look in Amazon you will find a plethora of books which might help both yourself and hubby. Make good stocking fillers for Christmas!!!!