I'm loosing hope .

I am a married woman to a woman . We have a donor and have been TTC for almost 6 months now. I don't sleep with him everyday, I only sleep with him during the week of ovulation and I still have yet to get pregnant. I went to the dr they didn't say I can't get pregnant but I did have my cervix scrapped 2 years ago . It's frustrating because 1, I'm married and not into men and I'm sleeping with 1 every month & 2. It's getting frustrating to my wife because she knows I'm sleeping with a man but still no results . Please help, any ideas are welcome and any advice. We want a baby so bad . We really do .