I completely agree that PTSD is an excuse to be the end all and constant target in a relationship.... we don't use it for other things, why with a relationship... that doesn't make sense....
Since he is so patient, so far, and you self aware of how you can sabotage things... that is a good place to start.... I would tell him I really didn't know what i need or want.... and that is where i am in my life in regard to relationships.... but you can share too, that you know what you DON'T need or want.... maybe a few conversations about this, starting this way, will help you and him both to see what you and him both need and want out of this...Cuts down on the some of the game changers down the line....
You don't have to tell him about your trauma at all if you choose not to, but can simply say, many things happened out of your control that has then causes you to have trust issues... with everyone, not just personal relationships.... and share with him that you are bringing this up because you don't want this to end up being an obstacle later.down the line.... that this is where you need to start .... and is he willing to go for this ride, because sometimes its a dark ride..... honesty.... being vulnerable, not with him per se, but with yourself..... and baby steps.... so he has a starting place to see if he is in this for the long haul.... And trust your gut.....that part never lies to us....
Love you and am so happy to hear you have a relationship in your life... and love the attitude of having nothing left to loose, only lessons to learn...... and just own you overthink things, and tell him that too.... it's not right or wrong, it's just part of who you are....but allow him , or ask him some of his needs and wants.... that will tell you if you have the stamina for the long haul.... go for it sweetie..... what would we do with a RDC who is happy???? Why , we would celebrate and dance the night away and be so damned proud of you for not letting fear stop you....
Keep us updated..... love you very much...