Broke up with 'BPD Boyfriend' of 3 and a half years

Hello again everyone.
I thought I'd like to check in as I split up with my boyfriend a month ago (on my birthday) and I thought I'd like to share my experience and perhaps get some guidance, as I feel quite lost at the moment.
I've posted about our relationship several times on psychcentral before (and various other places on the internet), if you're interested these are the previous threads I created throughout the years, starting with the oldest:
http://forums.psychcentral.com/partn...e-has-bpd.html
http://forums.psychcentral.com/depre...boyfriend.html
http://forums.psychcentral.com/depre...-distance.html
http://forums.psychcentral.com/partn...boyfriend.html
I re-read these threads today and was shocked to see all the problems we'd had laid out like that. Since the breakup I have been surprisingly OK, maybe because I'd already cried enough during the relationship...

So for those who are interested, this is a summary how it all came to a head:

Things didn't get better. I'm on my year abroad this year and found that when i was visiting home and while away I was always sick because of arguing all night, crying, missing meals because of arguments etc. I began to feel resentful to be missing out on so much. I had been unable to go out the last several times I'd tried due to arguing with my boyfriend on the internet, him telling me he wasn't ok with it or feeling **** in the aftermath of arguing. So when I finally went out, I was out of control. I drunk way too much, and I cheated on him. I finally did the thing he'd been accusing me for years of doing.
I knew I couldn't tell him, as he'd kill himself. And I knew we couldn't break up, as he'd kill himself (he'd been telling me that a lot lately). I talked to my mum and she agreed. So I tried to pretend nothing happened. But I got really sick, couldn't eat and was in a constant state of panic. So eventually I decided I had to break up with him, just saying I needed space from the arguing, not mentioning the real reason.
Of course there was a crisis, i asked my friend to check on him and instead she called the police. and he finally told me what happened to him to make him mistrust people, in an effort to get me to stay. He was raped continually by his older sister as a child.
He said that now everyone knew he was crazy (due to the police showing up), he didn't care to hide anymore, and would tell everyone and finally go for help. He said I wouldn't have to deal with it alone any more. And the doctor said what I thought was right: it wasn't just depression, he had at least PTSD. I messaged him and talked on skype whenever he needed me for a week or so 'as friends', and he gradually seemed to accept that, and said he was doing a million things every day that he'd always been afraid of. I thought it was going to be ok.
Then he showed up on my campus without warning, wanting to stay.I tried my best to be patient, to help him get home (he had no return flight, money, phone...had told nobody else where he was, couldn't speak the language...), in spite of his refusal to call his parents, or anything helpful, but eventually I broke down spectacularly, and he said sorry, he'd leave me alone until i'm ready to talk. I talked on the phone to translate for his hotel receptionist, and then received a text the n ext day letting m e know he'd got home and he would leave me alone. And I've heard nothing from him for 3 weeks.
I ask his housemates and sister how he is, and check his fb page etc, and it seems he's having a good time, but idk whether to believe it. Sometimes it feels weird not contacting him all the time, I still get anxious about having not texthim when I'm out for example. And I find it hard to know what I want and to say no to things. But otherwise, I've been not bad, which ironically has disturbed me a bit. I am seeing the guy I slept with. He's leaving in a month and I know its stupid but he makes me feel ok and he's not at all a worrier, which is a novelty. I feel like If I hadn't cheated and known I couldn't lie, if I hadn't been in another country, I would still be with my ex boyfriend. And I can see now that that wouldn't have been good.
I'm writing this today because I feel pretty low for the first time. I had a huge panic attack last night and today i just want to stay in bed. I'm afraid of what will happen when the man I'm seeing goes away, although I know it wasn't meant to last.

I don't know if this post is as informative as I wanted it to be, but there are so many details and also my memory is bad in times of stress. I'll let you know how I survive the next few months. Tbh I thought my world would be over by now, this new afterlife is very confusing. Any support would be welcome, or any questions I may be able to try and help with, to make me feel a little bit useful.

It sounds like you went through a lot of drama with this relationship. It's good that you are taking the break up well and ready to move on.

Update:
Well, he's gone (the new man) and I'm having a horrible time with anxiety and pain over it. Partly I miss him, partly I feel very insecure about whether he cares for me as much as he says he does. I told him to begin with that we didn't have to be exclusive, but now I feel horrible at the thought of him with others. I had a panic attack last night because I saw he 'liked' a photo of a girl from his home country. I know I don't want to live like this, I don't want a possessive jealous relationship, I want to just be able to enjoy someone's company and be ok with not knowing the future, and with something more complex than 'black and white' thinking. but i feel i can't help myself. Perhaps the fact he is so laid back makes me worry for the both of us. And the fact he's not unhealthily obsessed with me makes me insecure.
As for the ex, he's sent me a letter, and a text and re-added me on facebook. he's just said one or two 'friend-like' things, told me he's doing great and apologised for how he took the breakup. I think it will be ok. At the moment I know I won't go back. But I'm worried for the future. I feel so empty without the new man to fill the void.