I am a bit late to this thread. I am so sorry to read about what has been going on and I don't know if its moved on a bit as I have only read the first page of posts.
But you have just gone through what I had with my FOB. He did exactly the same thing, but when I pushed and pushed to know what he wanted and what he was thinking, he took me to court for harrassment - although if he had said anything to me about his thoughts I would not have contacted him. So now he has no contact from me and my baby will be born without him knowing.
I guess that some men are cowards, your boyfriend is young, but hes no child. He has a responsibility to answer and put your mind at rest. I just want to say that sometimes they are just ( well, I can't think of a word). But they don't change, my FOB is 40 and hes behaved in this disgraceful way. Just be careful not to get yourself into the trouble I have. I had no idea that a few emails (5) and (8) texts would constitute harrassment. But it did and caused me all sorts of additional stress
Out of curiousity I read about your situation with FOB and yes there are similarities although my FOB is not abusive in any way and I don't think he would say I was harrassing him, and if he does I don't really care. In fact I would like it if I heard something even if it did mean going to court because at keast the silence would be over!! But I think it's because I don't fear my fob in any way so there is nothing bad that could happen.... maybe a fine!!! But I wouldn't care. But I realise why you're advising me to be careful after your experience. And anyway he has never asked me to stop!!