Ask Me Help Desk - Is it the right decision?

I'm 26 years old and involved with a 31year old woman called (A) who has a 8 year old daughter from a previous marriage of 8 years. We've been together on and off for two years. Met her just after her devorce went through. We once again split up and became good friends and last year I went overseas for 8 months. I came back in December and we've been together since. Communication is not a strong point in our relationship, mostly my problem since I would take all avenues to avoid conflict.

We spoke about chidren in the past and she said the deadline is when she hits 32. I am not emotionally or financially ready for a child yet even though I love her daughter very much. We've never had a problem off excepting each other. Obviously (A) also needs security before we think about having a baby and she is also not ready at the moment. But time is running out. I'm not happy with my career and have been trying my best to better my current situation. Even been working overtime during the evenings. She has now informed me that she thinks children is out of the question. She doesn't know whether she has the strength to go through everything again. I can't except that because it is very important to me and I don't think I will be happy without that part of my life. I can understand and respect her feelings and it is clear to me that we are at different times and levels of our lives. Is it wrong to have such a selfish thought? All my friends having babies makes things even whorse.

Most of the times we split up in the past was because of her destructive lifestyle. She used to be very involved with commercial drugs. I would struggle with the idea of whether I should except it and maybe try and relax around the issue, but I will never endorse it. She hasn't used anything in the last 6 months since we got together again but we where visiting friends last week and she got a little drunk and wanted me to drive her to meet her dealer. Unnecessary to say we got into a fight and I took her home to sleep it off. She appoligized the next day and we carried on without discussing it further. Which in retrospect I realize it was a mistake, because it obviously still bothers me. I would think that if she knows how I feel about the whole drug thing that she would respect my feelings.

She has also been complaining a lot lately and it is starting to really irritate me. Back is sore, headache, tired, hayfever etc.

We've talked about just being friends a few times, but we somehow hide it and just carry on. I really love her a lot not to mention that she is very attractive and that I have a big atachment to her and her daughter.

I have been battling to talk to her for the last 2 weeks. I want to keep my option open for children and I don't want to be in a relationship where drugs is going to continue being an issue. I do not want my child to be anywhere close to such exposure in anyway. I pretty much have made my mind up about leaving her even though I feel bad about how it is going to affect her daughter.

What I want to know is whether I am making the wrong choice for wanting to break up with her since whe have been on and off for 2 and a 1/2 years? Am I selfish to think of myself in regards to chidren? Do you think it is OK to just write her a letter or do I need to discuss this with her? The last week we've been more like friends again and things are not too bad at the moment. Still, I need to do this. Should I leave this for when things are not as rosy? Also, we have not been intimate for the last 2 weeks, I think it somehow makes it easier to break up now since we are not that close. More like friends.

I really want to keep her as a friend but feel that I need to carry on and concentrate on my own life.

Hope you can give me some advise.

Thanks
Zach