Uhm, in my oppinion you are being taken advantage off. I think you have to stand up and take back control of your life and stop the rot before it consumes you.
This is your home a place of safety, comfort and reassurance, seems you have none of that, there. No one has the right to trivialise your time in the army and you have the right to display and be proud of your awards. As for the dog, well that was down to whether the children got on with the dog or not, the ex should have no say in your day to day living, unless it adversly affects the children.
This though is between you and your partner, you have to sit down with her and tell her exactly what you feel, what you intend to do about it and ask her to make her mind up as to who she wants to be with, her ex or you. She chose to leave him and make a life with you, when is that actually going to start.
I would be insisting that the ex finds his own accomodation, does not use your address for his personal business and returns the key to you asap. You can even change the locks.
As for not allowing you to lay down boundries for the childen, well sorry this is your home too and if you are to live as a family you have to be able to act as a family and get the respect you deserve in your own home.
So he only has to make the drive twice a month, but you should commute three hours everyday!!!!!!!!!! Sorry chum, if you give in to that, you will be facing a whole heep of health troubles and more. It is not realistic. I can inderstand wanting a college fund for the kids, but at who's expense! If you have to pay for the whole sheebang then you have the right to have an oppinion of how it is spent and where you base yourself to earn it.
I think you and your partner need to see a councellor and get some real honesty and communication going. You will have to prepare yourself though for her to be so content with the set up as is, she sees no reason to fix what for her is not broken!!!!!!!!! Are you able to face the fact that you may have to get drastic and lay down ultimatums, because that just may have to happen.
Either way, I wish you all the best and hope you find a resolution for you all.
Winnie.