You seem to be constantly looking at your weak point, turning on a spotlight and viewing it through a skewed perception of it. I know you'll either ignore this or argue my point but you repeatedly blame your shortcoming that you think you have as a reason to blame for your inability to find a date or a partner.

So you aren't quick witted, as you say. it's funny you say that you're slow thinking yet the fact that you spit out what comes to mind doesn't seem slow to me, it seems more that you just say what's on your mind in the spur of the moment and that's not slow thinking that's impulse control. So learn to tame your impulse control. People are going to be more open to someone that takes their time in answering or replying rather than someone that just impulsively feels the need to blurt things out at times.

Also if it's a matter of saying stuff that seem out of place, don't get me wrong I understand that, I've been there and especially in the face of a girl I'm attracted to.. that's not slow thinking for me, but just embarrassment, flustered moments and just social awkwardness.