Acceptance is usually won over eventually, but it can take a long time.Your new partner may truly be a wonderful person but many friends and family that are close to you are going to be so prejudiced that it will be hard to give the new person a chance.Of course you should not make your decisions based on what others would think or feel.
Sometimes relationships that start as affairs serve as an escape from difficult interpersonal dynamics in the primary relationship.
Feeling torn between two lovers can be an agonizing experience.
Besides the guilt, and fear of discovery, you also know that sooner or later you will have to lose someone you love or have loved.
Can the two of you exist in a relatively socially isolated situation for some time?
Losing a long-term partner, even if things feel bad, is still a loss and needs to be grieved.