Yeah, Wanderer I think from what I've seen that this is something that INFJ males are especially prone to, although I admit that most I have known have only been online.
I actually agree with what Vicki Jo is saying. That's not to say that one shouldn't be wary of the person or circumstances which put their defenses up. It's just that when you are feeling bitter or angry and erecting barriers around you, you cannot move on with your life or absorb the care that other people have to give. INFJs generally are pretty prevention oriented and avoidant of what could put them into unresolvable circumstances, particularly in an emotional arena. Therefore it makes sense that when we get hurt, it determines us to never put ourselves into a position of allowing that to happen again.
In addition, I think INFJs have a tendancy to suck up more inconvenience or frustration than they should in a relationship or friendship simply because they can predict their own response better than the other person's, they want to be accommodating and not high maintenance, it takes them some to sort out whether their initial negative feelings are reasonable, and sometimes resentment at the imbalance can sneak up before they realize the enormity of it.
I guess it depends what has happened to you in the past how difficult it is to resolve the problem you are facing. I'm assuming though that it's fairly serious. In my own experience, it is only God's supernatural power that I've seen offer the ability to let go of all that. I believe that attachment brings about resilience. Attachment to a just being whom I believe created me, has control over what ultimately happens, and who is sinless and will never let me down even though others will can allow a kind of resilience to develop in circumstances that would normally crush us.
Aside from that though, the passage of time helps to add perspective, so long as we don't become so ingrained in these new attitudes, outlooks and habits that they take on a life of their own aside from the original problem. I think one problem for INFJs is that the Ni ability to shift perspectives can just create a bewildering mess of emotions to wade through. In interests of moving on somehow, sometimes we end up just picking a point of view about how things are and sticking to it. I've found that space and distance from whatever is creating those conflicting feelings allows me to process them in a more healthy way or at least let them settle enough that I can revisit the issue some time later with better results.
You cannot be close to anyone unless you have a sense of trust in them and can be vulnerable with them, so your concern is a very valid one. I think awareness of what is going on with you is the first step in changing it.