hello homerbart, hope you are feeling less down today.
I am sad for you having to feel this way about your dog, and I do know what you mean. Sometimes it isn't fun nd games at all is it! My Collie was such hard work for such a long time, and even now there are some situations he just can't be in.
wolf is so right, it sounds as if you love him very much, and it is worth sticking it out, if you feel strong enough.
Try to do some fun training with him in short bursts, using lots of treats and praise. If you have to, use an extendable lead while he gets used to coming back to you in all situations every time.
I think that he needs to know he must respect you. So little things like not letting him dash ahead of you through doors (I don't mean to patronise, it might be stuff you do already, it's just that it was stuff we didn't know about initially, and with Jack being our first dog, we have had to learn such a lot!).
I know terriers can seem inexhaustible (is that a word?!), but mental exercise should tire him too, so it doesn't always have to be physical exercise. Maybe those dog puzzles by Nina Ottoson (I think) available at www.surreypetsupplies.com, or a treat ball that he has to spend time figuring out in order to get a reward.
I am sorry to go on, but I would be so sad to see a good, loving owner have to give up a cared-for dog, when so many dogs don't have a good home. x