time heals... blah blah it's a cliche i know...but true. i know at the moment it seems like you will never get over it - and that may be true but it will get better.
i had to watch my dp go out with one of my best friends after we broke up and had to see them both alllll the time at a time when i had no-one and was very unhappy being single.
but i learned to be happy and i;ve met someone else and im so proud of myself that i've managed to come through a time where i thought i'd never survive because i was SO unhappy.
I did though---i'm with a wonderful guy now and i would never have met him if i had stayed pining for my old boyfriend. I took some time for myself and the pain does heal..or at least dull.
I knw it sounds cheesy but - if i can do it so can you! lol.
another option is to try and get him back but that's a whole other story! - now there is someone else involved and you don't want to hurt their feelings....
also before you even THINK about telling him that u made a mistake breaking up with him and that you've been wanting him back - you need to calm down and sort yourself out a bit so that you're prepared to hear 'no' if that's what he says...you don't want to come across as the crazy ex-wife!
be calm, and confident and grounded - someone he would want to be with more than the person he's with now) if you know what i mean.
if you ever decided to bring up the subject of getting back together - maybe would be best to wait until he is single (b/c the person he's with now is prob just a rebound?) and the initial sting of breaking up has dulled a bit so you both are more rational.
also good tips to make yourself feel better and try and move to a positive place when you feel down:
excersize(sp?) - yoga, walking.
sunlight
warm bath
relaxing music
deep breathing - focusing on your breathing and letting all thoughts melt away.
writing a list of all your achievments/things you like about yourself
getting your hair/nails done (pampering)
focusing on something (cleaning,organising)
focusing on setting goals i.e have a shower, walk dog, choose outfit to wear that day.
don't go over and over the details. it's happened now and you can't change it.
don't blame yourself - you broke up with him for a reason right? who's to say it would even work a second time around?
know that each day that goes by you will feel a TEENY bit better even if it's only a miniscule amount.
maybe go on holiday by yourself or with a friend if this is an option.
make a list of all the things that make you happy about the world. think hard! lol.
anyway this is prob all useless advice - feel free to ignore it. im just remembering back to when i felt like you did. xxxxx lots of hugs. you WILL get through this a stronger woman. xxxx