Open relationships and how they make me sad

Recently I haven't been writing as much. I put this down to something I call the 'depression-humour' curve. When I'm a bit down, but not full blown depressed, I make a lot of jokes to pull myself out of it and make light of the situation. I think this is due to the fact I live in England and there is nothing more that we love than being self deprecating to the point of near suicide. But then I hit an ultimate low, and the curve plummeted downward as all the depression came and all the jokes up and left. Those little bastards.
I was thinking about why I was suddenly plummeted into a world where all I listened to is The Smiths and chain smoked and drunk black coffee with so much sugar that I now have an actual hole in my gum. Then after about 2 seconds I realised it was my current situation with BOYZ.
As a feminist I try to not let the opinions and actions of males dominate my life. But then I think regardless of gender I am going to be effected by the people around me (OK if this is wrong I'm sorry but I'm just trying God). Recently I embarked in an open relationship with a bloke who is nearly 3 years older than me. Its complete and utter deterioration sent me reeling into the world of weepy sad teenage girls.
Here is a list of things which went wrong:
1: He slept with 5-7 people and I slept with 1
Although open relationships are not a competition, I sure did treat it like one. Boy oh boy. My jealously stemmed from the fact that he was beating me, which led to a lot of nights trying to get laid but then getting too drunk to actually doing anything (sidenote: I must pick good guys, one even left a note next to a glass of water which said you were too drunk so I got you this water and got the bus home, bless)

2: I walked in on him once
With another lady. Now anytime you have feelings for someone, you want to be with them and only them. Seeing them doing all the things you like to some other girl at 3 am after your 3rd bottle of pinot grigio results (in this case) in complete crying breakdown followed by throwing the bottles at the bricks of his house (sorry about that all of his housemates)

3: I liked him more than he liked me
It was pretty obvious. I was way more into him. I'm 19, I come from the countryside and now I'm at a hip uni with hip people. He was one of them. 

4: I'm a jealous person
One piece of advice I would give to anyone embarking on an open relationship is make sure you are not the jealous type. Also make sure you can differentiate sex and 'real feelings'. Also make sure you use a condom. Also don't sleep with their friends. OK that was more than one piece, I'm just trying to help you out though.

I think thats pretty much it. Currently I am trying to get in contact with him because he has my favourite jumper, a quest which isn't really going anywhere. The loss of this jumper is a physical representation of all the bad decisions I have made over the past 2 months and if I never get it back it will be a beautiful learning curve. But I will be super pissed off. I love that jumper.