I'd rather be honest and true to myself, rather than keep up any lies. Those kinds of happiness will just be temporary anyways, and will be eating you up on the inside. Better to break free and live an honest life. Sure, you may be in pain at first, because you're not used to this life of solitude and not depending on whoever it is that you used to hold on to. But take comfort in the fact that when this happens, when you're in so much pain, after a while your mind reverts to survival mode. This is when your psyche starts getting sick of being unhappy that it uses up all its resources to make itself happy again. You'll find yourself even friendlier, and more pleasant around people, because basically your mind is just trying to do all it can to avoid letting you remain hurt and lonely. (See, who better to take care and look out after yourself, than... you yourself? Lol). New friends will be made, old friendships will be solidified. With the socializing in this state of mind, you will often find new doors opening up for you. This is when the magic happens. So go for the ride, and life will only get more interesting, so much better than before. Constantly growing as a person. Rest assured you're always gonna be better off than you were before.
Ps. Sad to say though, that the people that I had to leave behind in these situations (because they were the source of the pain) often end up in pretty bad predicaments (not my doing, of course). What can I say, "What goes around, comes around". We'll be better off living a constantly improving life, while those who wronged us pay the price of what they did. That's why, do good, and don't give a fuck about those who make life worse. Leave the bad behind, and keep trooping on.