Hello
@xtineI care for my husband who at one stage was been diagnosed with a personality disorder (not otherwise specified) but this has been changed to bipolar ii.
Mental illness puts a great deal of strain on even the most robust of relationships and I think the answer to your question is quite a difficult one and is likely related to a number of contributing factors.
'Affect' is the facial expressions, tone of voice and demeanour a person gives in response to how they are feeling. This is often reduced ('blunted' is the medical term) or inappropriate in someone with StPD making it difficult to read their non verbal cues. They may laugh at something that is not funny or may not show excitement if something really good happens. This would make the reading if his body language a lot more difficult for you.
No healthy relationship is without disagreement and being able to resolve conflict in a healthy way is essential for both parties to feel safe and secure with each other. From what I understand the very nature of StPD means that someone with this disorder will have difficulty making and maintaining close relationships. What you see as a problem may be quite normal to them.
Intimate relationship are often not sustained in the long term with sufferers if StPD as the usual expectations of what a romance entails needs to be thrown out the window. Those with StPD do not have the emotional skills to show affection as would be desired by a partner, for example one often does not get hugs or smiling in response to affection being shown. Their ideas of reference and odd thinking often means that they become paranoid even towards the ones they are closest to.
You articulated yourself that you are not getting empathy and understanding as you would no doubt want, this can be another trait of StPD and your boyfriend may lack the ability to provide this. I do not know if this is something that can be learned.
I have attached a link that may be of help to you.
http://outofthefog.website/personality-disorders-1/2015/12/6/schizotypal-personality-disorder-stpd