It's a natural feeling as the others have pointed out. When we've been hurt by someone......it doesn't necessarily have to be an ex............it can be friends and relatives.......................IF we have not received closure..................the desire to express our hurt lingers.
^This does not mean that you haven't moved on. You say that you don't love him, this is the indication that you've moved past him. But it's normal for us.....when we've been treated unjustly........to let the offender know how we felt.
Closure basically refers to venting your feelings to the one that has wronged you. However, it CAN **be difficult to obtain the desired closure for several reasons. For example, sometimes it's not possible to get a hold of the offender. And other times..........even if you do get the chance to express your feelings to the offender.........the offender might be so narrow-minded and inconsiderate that he/she will **NEVER acknowledge his/her mistakes or show remorse. In such situations........it is up to YOU **to provide **YOURSELF with closure by reflecting over the lessons you've learned.....being grateful for what you have now.........and by thanking the jerk for teaching you (through his non-examples) the true meaning of love, committment, trust....and just basic good character.
As **Psquared **suggested, spend time with your husband in making your marriage even stronger. Focus on the accomplishing the goals that you both have set and also focus on developing yourself as an individual too.
The reason you felt disturbed is because most people feel akward running into those they share an uneasy relationship with. As I said earlier, it's not only confined to exes. People feel weird around their former bosses........former crushes........former friends..........former colleagues........former crushes.............you name it.........you'll feel an emotional disturbance in meeting someone who screwed you over in some way or the other.
Now about the "weird look" that his wife gave you...........you never mentioned what kind of look it was, lol. Was it a scared look? An angry look? Evil look? Dirty look? A nervous look? A constipated look? If she appeared nervous or scared or uneasy.......it's natural. Most women would feel weird around their husband's former flames. However, if she was giving you the stare of death...................she's insecure and immature. And you're handling the situaion a lot better than her, lol.
They say that happiness is the best revenge, Chameli. Don't allow yourself to become sad over someone who can't respect you. It's not worth it. Revel in what you have......and it'll show to the world (and him) that you're happy and secure with the way life has turned out. Also, I believe in the power of what goes around comes around. Somehow......some way.......what we put out there........good or bad.......has a strange way of finding us. You say that your ex appears happy. Ever hear of the saying, "The grass always appears greener on the other side"? It's possible that he's happy in public.....and miserable behind the four walls of his own home. It's possible he's not fully satisfied with your life as you are. It's also possible that.......days/weeks/months/years.......down the road........he'll be screwed over by someone in the same way you were. Maybe someone whom he trusts (a relative, friend, coworker) will betray his trust the same way yours was betrayed. But don't wait for him to receive his just deserts.........Allah knows the best time to teach lessons. Meanwhile concentrate on making your life even better than it is now :)