I agree with the PP who mentioned acceptance. I used to be a very negative thinker - having a nervous breakdown 10 years ago and losing my marriage and almost my sanity was a big wake-up call as to where negative thinking can lead for me.

It has taken me a long time, observing other people and a bit of reading about Buddhism to come to a more positive mindset. DP, for all our difficulties, is an exceptionally positive person so that has rubbed off on me. I'm going to give two examples but I really try to be more positive every single day, not just on the big issues like the ones I'm describing but also the small issues too.

When I was in my mid to late thirties, single and childless, I decided that I would have a red hot go at finding a partner and having a family. I also mapped out my life if that didn't happen in terms of what I believed would bring me fulfilment. My nervous breakdown had taught me that I believe the meaning of life is helping and nurturing other people so I decided that I would focus on that in my career and my everyday interactions. Once I was at peace with WHATEVER happened, whether I stayed single or had a family, I met DP and had my two girls.

Fast forward. DP and I do not have the greatest relationship at the moment. Infact, I'm on the brink of calling it a day. Again, I'm at peace with whatever happens. Six months ago the thought briefly terrified me. I was mess for a night but over the course of that night I reached a point of acceptance. I know that I will cope whatever happens. I committed to myself that night to leave no stone unturned in trying to make it work but not to stick it out for the sake of it either. Negative thinking could lead me to a place where I thought that I would never find another partner, never have a happy family life and the girls would be stuffed up. I could also beat myself up for having two 'failed' relationships. Although I would much prefer to say that I've been married to the same guy for 15 years, I can only look at what each of those relationships have taught me, what I've learnt about myself, what I've learnt about life and what I've learnt about how I want the rest of my life to go. Positive thinking allows me to embrace the thought that the past is just that, the past and the future is to be embraced. If we do break up, I will focus on thinking that I will be just fine on my own and at some point, I will make an effort to find a partner with whom I have a healthy, loving and supportive relationship.

As the others have said, in your situation I would steer a middle course. I DO think that telling yourself that you definitely won't get pregnant could well harm your chances but positive thinking does not guarantee success either. I would look at positive thinking as giving yourself your absolute best shot and that's about all you can do. As someone else said, if you've done your best then there's no cause for regret.