Leelee…..there are some practical, concrete things that you can do if you are really serious about wanting "help".....I say "really serious", because many people just want someone to magically take the pain away without having to do anything, themselves...lol...
one thing that helps (and, I have done this)...is to write down the top worst moments in the relationship and how it made you feel, at the time, on a piece of paper. Carry that paper on your person, at all times...and when you are missing him...read the list over....even if it is a dozen or more times a day! Even if it makes you cry.
Another thing, is to find an alanon group, right away...or, even better (for you)...call your local domestic abuse organization and ask to see their counselors or join their support group....
Face to face support from living, human people is very powerful....don't underestimate this.....
Also, begin to read and study the materials that are suggested, here....knowledge is power....study and read some, every single day.
Another thing is to cut off all contact...if you haven't, already.....any contact, whatsoever will increase your pain, all over again.
It is vital that you understand that you are grieving the loss of the fantasy of what you wanted the relationship to be...and, the first weeks to months of grieving is very, very painful. Three months is too soon for it to be over....grieving is the first part of healing...and, there is no pain-free way around it. I will gradually lessen...as you continue to heal....
So many people throw in the towel because they do not understand that the pain will gradually go away....
I call it the "short-term pain" for the "long term gain".....
Another thing...keep a very structured schedule...with exercise every day....
And....allow a certain time of day...say, nine o'clock, at night for example to grieve as hard as you can....about one hour, for example, to start with....cry, scream, allow yourself to be really sad....read over your list of bad things and write your feeling on paper (journaling)…..listen to sad music, etc....
Make sure to do this every day...at first....
(this is a form of what I like to call the "wailing wall" exercise.....
By doing these things...you can work yourself through the grieving process....and, you will laugh again, one day...and the sun will shine, and the sky will be blue and the birds will sing, again.....
***I do agree with the "trauma bonding"....that Mango speaks of...that is why I suggest that you call the domestic violence center and arrange support through them....