It's been four years since I have not seen or spoken to my ex; now she's contacting me through email and I'm responding. It's just friendly, but I'm feeling blue and confused. I am with someone now that I love (we've been together for three years). Is it possible to love two people at the same time?
Had you asked me whether or not you should get back together with an ex whom you miss and who makes you feel loved, then my response would be: it depends on the circumstances of the breakup. Often we go back to relationships that were dysfunctional, which is why we terminated them in the first place, and our inability to move on is just another symbol of that dysfunction. Those relationships cause far more confusion than clarity.
However, in your case I won't even ask about the circumstances of the breakup, because you are telling me that you're with someone else whom you love. You cannot violate that relationship by dipping back into the past. It is troublesome that you would even consider forsaking someone whom you claim to have affection for, just because an ex has come back into your life.
This is an issue of morality and ethics. The question of whether we can love two people at the same time has nothing to do with whether we should love two people at the same time. The answer to that is, of course, no--it is immoral and unethical. A relationship consists of two primary ingredients: primacy and exclusivity. You have to make the person you're with both the most important in your life and, certainly, the only love in your life.
Incidentally, I do not believe we can love two people at the same time. While we may be attracted to many people at the same time, we can be sure that this is simply attraction--not genuine love or affection.
I would advise you to allow bygones to be bygones and leave the past in the past. Work on cultivating a special relationship with this woman whom you say you love. Remember, one of the most important parts of a relationship is learning to feel satisfied in your connection, not always looking over your shoulder to see who else might be available, or who has suddenly come back into your life.