Well, firstly you have the sheer emotional difference between males and females, being males generally show little emotion to begin with. When you compare a male and a female with PTSD, the female will still generally have her emotions intact, maybe not completely, but generally far better than a male will.

Secondly, PTSD invokes fight or flight, thus our bodies are in a constant state of readiness to act, thus to act clearly, our mind removes our emotional capability, or suppresses it to be more precise. We still have emotions, we have just buried them to help ourselves survive and cope with the world around us. It is human nature that the strong survive, thus we tend to process this as the aggressive, or the fearless, all of which have little scope for emotions to clutter the thought patterns.

Remove the anger and aggressiveness, and we allow ourselves to become vunerable. Generally, vunerability is a sign of weakness, though we know that isn't always true, however; each individual will process this differently, thus some will show emotions, and allow themselves to be vunerable with PTSD, others will remove their emotion to grow strong, aggressive and fearless.

Are we wrong to become this way? Well... yes, I believe so, however it is not something we cognitively absorb or realise at the point when PTSD is taking over our mind and body. PTSD doesn't just popup, it stems and grows upon a person, to a point where you no longer recognise yourself. At this point, it become more difficult to break the chain, break the cycle, and allow ourselves to become vunerable again, and trust those around us with that vunerability we expose, hence we keep it hidden, locked up, which is an emotional state of numbness basically.

The chain can be broken, it is hard, but achievable. First you start with the anger issues, through identifying emotions again, which are what produce anger. When you can identify emotions again, you can begin to feel them, instead of allowing them to create anger. When you begin to feel again, you allow yourself to become vunerable, though we tend to only allow this to someone we trust with out lives, not just everybody.

Fight or flight is something that will stay with a sufferer their entire life, though it can just be made a better to work with emotions around those we trust, generally our spouses. I have exactly what you are describing and having difficulty with your partner, and it is something I am still working on myself.

For some reason we tend to be capable of showing emotion around children, because children don't go out to hurt you, so we immediately feel at ease with them, and allow ourselves to be vunerable to them, because we know they don't have the capacity to be spiteful, or hurtful towards us that could deeply affect us. Adults however do understand this, and do attempt to do it to one another, so we tend to tighten up with adults, yet be vunerable with children.

It becomes very much a trust issue I think at the end of the day, and when PTSD is uncontrolled, we often trust nobody completely apart from ourselves. This is totally wrong to do, but it occurs as PTSD takes control of us.