I see so many relationships that are torn apart because of issues that weren't dealt with in the past. People hold onto resentment, anger and hurt, and it becomes a part of the relationship. Whether the issues are part of a previous relationship, or whether they are part of the new relationship, you will never be able to move on until they are dealt with.
Some of the most common problems include:
• Distrust of the partner due to infidelity in the past (a lot of the time, it was a previous partner that was unfaithful, not the new partner).
• Fear of addressing concerns in the relationship in case they lead to violent outbursts or irrational behaviour.
• The inability to identify a specific issue, but harbouring a feeling of resentment every time your partner does something small to irritate you.
• A history of physical, emotional or sexual abuse.
• A history of failed relationships and choosing inappropriate partners.
• Interfering parents/friends/family members.
• Guilt over something that happened in the past (which might not even have anything to do with the current relationship).
Remember, relationships are not like band aids. You can't just put a new relationship on top of an old wound. You need to heal the wound first before you can move ahead. You may still have some scars, but at least you will have dealt with the issue and you know how to move on from it.
It is not fair to expect a new partner to deal with issues that happened in your past. I see so many couples that suspect infidelity in their new partners because they have been betrayed before. The new partner has to deal with being blamed for something they didn’t even play a part in. If you have experienced deep pain and hurt in a past relationship, I suggest seeking counselling before beginning a new one. That way, you will be able to offer a 'new, whole and confident' person to your new partner.

We all have relationship problems and addressing the problems and communicating with your partner is the best thing for any relationship to proceed.