I am not going to presume that your experiences with adultery constitute sin— it sounds as if you might have already made that judgment upon yourself. But adultery is certainly a violation of accepted mores. You say that you felt great affection for this man, and those feelings seemingly justified your, and his, actions. Even though you may have known that it was wrong, you did it anyway because it felt so right to love as you did. Of course, there are far-reaching consequences to such actions, and maybe you also experienced some of those, or saw them in the other people whose lives were affected by your decisions.
Love in its purest sense is the desire to do good to others—but real love must encompass all of our brothers and sisters, not just a special one here or there. Real, honest love will never be consciously selfish or hurtful to another—and that includes the spouse and family of the married man.
Maybe you'll be comforted by this quote of Jesus From The Urantia Book:
(170:2.23) Jesus taught that sin is not the child of a defective nature but rather the offspring of a knowing mind dominated by an unsubmissive will. Regarding sin, he taught that God has forgiven; that we make such forgiveness personally available by the act of forgiving our fellows. When you forgive your brother in the flesh, you thereby create the capacity in your own soul for the reception of the reality of God's forgiveness of your own misdeeds.
In order for you to feel forgiven you must now proceed with the business of forgiving all of those in your life who may have wronged YOU. This is no small task for most people, but it can be easily accomplished with the right frame of mind. It may include forgiving your former partner, as well.
Learn to look for God's will in all of this, and try to see a bigger picture. Get your mind off of yourself, and try to see in others the same kinds of personality foibles that created your own misdeeds, be they pride, greed, arrogance, or selfishness. Remember how easy it was for you to fall prey to these, and it may be much easier to see how another could err in the same way you did—maybe not by doing what you did, but in other ways. Then, forgiveness becomes easier. Eventually, you will find God's forgiveness in your own heart, if you open that heart to real sympathy with others and the trials they experience. Set everyone free from your own judgment.
The fact that you are remorseful is a good sign that you may now think more carefully about it if you are ever again faced with such a possibility. You know by its consequences in your, and other's lives, that what you did was not good, not Godly, and you can amend your life in accordance with that knowledge—and also, maybe help others who may be tempted to fall into the same trap. And I think you'll agree that it was a big trap.
We all make mistakes, and we all fall short of our highest ideals. It is the human condition. But the important thing to remember is that in every moment, we can make a new start, and we can change our ways of looking at things so that we don't repeat those mistakes again. The consciousness of guilt and remorse is the way we know we have done the wrong thing, and it speaks well of you that you are taking that to heart, rather than continuing to justify your actions.
But also I would add that you must forgive yourself. Stop dwelling on those feelings of regret, stop beating up on yourself, wipe the slate clean and start fresh with your life. This might be a good time to re-assess what love really means to you...? With God's help, fearlessly address the personal shortcomings that created the mental atmosphere in you in which you felt justified to proceed with your acts, and ask him for healing in those areas. It may not happen overnight, but it will happen if you remain sincere of heart.
Most importantly, remember you are a beloved child of God—stand firmly on that solid truth—and he will never forsake you when you ask him for his help and mercy."