Hello everyone, first post.

So my partner has BPD, and was diagnosed about 4 or 5 years ago. I met him coming up for 4 years ago, and in this time there's been a lot in our relationship.

I have read up on BPD so I could have an understanding on some of the things that were happening, but I'm beginning to wonder how much can be put down to borderline, and how much is just him.

To give some background, when I first met him he was still seeing someone else for over a month before I found out I was the other woman. He lived up the north of Scotland, and she lived near the south. They were together about 4 years, but he claimed he didn't love her, however, wanted to split with her face to face. As I found out, he called her that day and ended the relationship. 

Well, this cheating has been constant for the 3 years we've been together. Like double numbers for exchanging information, seats etc. He met up with a few of them as well.

On top of this, of he goes out and drinks, he has no limit on stopping. He turns into a nasty person who can ignore you all night and not reply or pick up. As he has to walk busy 60mph roads to get home, I'm worried sickless. We've spoke at great length about how his actions effect me, but it seems to be in one ear and out the other.

I love this man and have taken a LOT of anger from him when he's confronted with evidence about his actions. We ended up splitting last November due to how bad the relationship had gotten, but have ended up together again 2 months ago. 

We spoke again about what went wrong previously, and for me it was obviously the cheating, quick anger (like to the point a simple discussion if it starts to annoy him jumps straight to anger with no in-between ground to work with), and also his behaviour when out drinking. 

Well last night it was like the last 3 years all over again. He met up with a pal and started on non alcoholic drinks. That didn't bother me, but what did was he was out with his dad and was gonna be going home as he's hurt his back so badly he's on pain meds and had to cancel and hour before hand getting on a train to see me. I asked him why he wouldn't say he's going out, so I know why there's a reason for lack of contact and he ignored that message. The night has went on and I've heard nothing from him. I ended up in A&amp;E due to something that happened at work, and no response from him.

He's stayed out all night knowing I'm worried, went to alcohol, and not answered any messages or returned phone calls. 

I need an understanding if BPD is a factor (not the whole cause) here or if its just him being an ass?