i think that given what you went through with your ex, it's a natural knee jerk reaction that you probably will have for a while. it becomes hard to trust anyone after you have been through a bad relationship especially where the ex has manipulated you in any way. automatically the guard walls go up "why is this person being so friendly?" , "what are they after?" , "what is this person up to?" you start to take a cynical view of everyone and everything all because of the past, i subconsciously do that too at times, he probably was a really nice guy...but, maybe he wasn't hee hee. i used to give people the benefit of the doubt, everyone is ok until they prove otherwise...unfortunately i have found out that that can be a dangerous way of thinking..i have been burned several times by ex's so it's been a hard road, so after so much trauma it makes you that way, ya know...just my 2 cents hope this helps!