Re: looking for someone who has experience with OCD
"obsessed" is a term that gets tossed around a little too loosely these days I think. It sounds like your girlfriend has some personal emotional issues as well as some trust issues which are normal for any relationship.
A person with OCD experiences severe, debilitating anxiety over their worries - which are usually very irrational in nature.
Traumatic life events can definitely lead to cautious behaviour when it comes to uncomfortable territory in order to prevent a repeat of past events, but I wouldn't go as far as to say she's obsessive about it.
I'd say just be very patient with her and let her work out her problems as she see's fit as long as it isn't detrimental to you personally. Let her know that you're there for her and help her to understand that you're supportive and understanding of her issues as she works through them.
At this point i'd say the last thing you want to do is put a label on it like "OCD". Assuming the worst before its confirmed is never a good idea.
Best of Luck,