Losing my lovers, loving my alcoholic mom

Two paragraphs is certainly not enough to know if having an alcoholic mom was enough to cause difficulties in your romantic relationships. However, it is possible, especially if you feel that you have no problems with her.

Parents are our role models for intimate relationships. For better and for worse. As a good, loving daughter you accept your mom with all of her qualities, for better and for worse. You are very used to her and appreciate her sweet and loving ways. 

But in your mother's life there is an additional relationship that made her unreliable in many ways, some obvious and some subtle. You know that a person can be worthy of love and be unreliable. It could be that there is a sense of unreliability in your love (romantic) relationships that you perceive as instability and infuses a negativity that disrupts the relationship. Mind you, this is just an initial hypothesis. If I know you better, this though might prove wrong (or right) or we might come up with other possible reasons.

As a therapist and a coach I can see the two possible ways for you to approach this problem. If you want to do therapy, a therapist can help you delve deep into your past and uncover patterns of behavior that have and are contributing to your behavior that is sustaining this difficulty maintaining romantic relationships.

You can also employ a coach who can help you set goals to get over your obstacles in your present and future relationships. This would not focus on your relationship with your mother, but might utilize your own ideas expressed and not expressed) of what happens in intimate relationships. 

Another advantage of having a coach is that, since it won't focus on your relationship with your mother, it is less likely to disrupt your relationship with her. 

As always, I strongly urge you to get qualified help. There are many relationship coaches out there, but since that is an unregulated industry, there are also many unqualified people. Someone who is both a professional (social worker, psychologist, counselor, etc) and  coach is preferable. If you would like to talk to me about this further, my information is on this website.