Excellent. Now we will get somewhere.
First...You are speaking to someone experienced -- marriage. I was married once and divorced. So am not talking out of my @ss. Am not saying I know everything about women. Anyone who said so is either a liar or an idiot. My (ex)wife cheated on me, so she did me wrong, and that made it much easier for me to get over that relationship.
Now...The worst thing for you is to be alone. It does not matter if you are out with family or friends. You need to get out of the house or apartment. It is not going to be difficult as outside, you will see couples happy with each other and you are alone. You will see signs of intimacy that you once had. But then, how is is better if you are alone and your mind is occupied with the thoughts of what you once had ? Get out of the house/apartment.
Next...If you are with company, avoid talking about your (ex)gal. Your family and friends should understand that talking up about you and down about her would only make you feel worse. And it will. I have been on that route. Do something, anything, that will occupy your mind. That does not mean going to see a romantic movie. If you are going to see a movie, see one that has car chases, explosions, martial arts, and gratuitous displays of boobs, in other words, the 'manly' kind.
Next...Do not get involved with another gal immediately. You will meet other women, of course, but do not see any as a replacement for your (ex)gal. A replacement implies something matching, as close as possible to the original. Do not do that. It may sound counter-intuitive, but being unattached for a while is a good thing. After my divorce, I was unattached for yrs before getting involved emotionally again. That does not mean I had no 'booty calls'. I had female 'friends with privileges'. Note that I said unattached, not alone.
Next...Eventually, you
WILL find a gal who 'clicks' with you. The important thing is that you do not see this gal as a replacement for your (ex)gal. Judge her as a standalone person, independent of any standards you may have had with your previous gal. Doing this is being fair to both of you, especially to her. No one, man or woman, likes to be assessed base upon someone else in the past. Women already do not like it that men judges them according to what the guys sees in the movies or in Victoria's Secret catalog, but now she found out that you are judging her based upon a woman who left you ?
The process above works with 9 out of 10 men, so odds are it will work with you. How long will it take depends on how much are you willing to stick with it.
So to start off, get out of the house/apartment. Go to gym more often. Volunteers with kids. As a motorcyclist, I wholeheartedly endorse that if you do not know how to ride -- learn. A bike will keep you physically and mentally busy all day long. Do things.