Do you have any thoughts on the fear of abandonment?
The most important thing right off the bat is to realize that people are sinners, but God is good. People do cause hurt and pain, and do mess things up, but God says that He will never leave or forsake us (Joshua 1:5, 2 Corinthians 4:9, Romans 8:28). From there, I’d say that you need to realize the issue(s) if you don’t already, so that you can begin understanding and working on them. If you’re a Christian, forgiveness is key – this doesn’t mean forgetting or downplaying the consequences, but forgiveness is the first step toward reconciliation and healing. Also, going to a good counselor is a huge step. Counseling isn’t just for crazies (even though we are all crazy at some level), it’s for everyday people to work through issues and be able to live a more fulfilling life.
On the more practical side, I think you’ve got to realize how the fear influences thoughts and behaviors. Are you emotionally manipulative to get people to stay and/or express their feelings of love? Are you willing to compromise morally (sexually, etc.) in order to keep someone from leaving you? Do you alter eating and/or sleeping patterns because of worry? Once you get that out on the table, it’s good to go through these issues one-by-one and see that any of these behaviors are sinful because they aren’t born out of love, but rather fear and hurt (1 Cor. 13, 1 John 4:18).
Finally, I think trust plays a huge role in dealing with abandonment issues. Trusting that God will get you through the pain and fear, trusting that your husband/wife will stay (this can be most achieved by them loving and having a holy fear of Jesus as well as a covenant of marriage with you). The key isn’t to make sure nobody leaves you; it’s dealing with the original hurt and realizing that your hope is in Christ, not in humanity. Along with a good counselor, I would recommend writing and then voicing your concerns to loved ones (after reviewing and revising them), letting them reassure you, and then having a good accountability partner and/or group to walk through life with so that you can mediate your thoughts and behaviors – not just on abandonment, but everything else.