Honestly? I think you should try a real method of NFP. Using condoms on days that you think you might be ovulating is almost a guaranteed way of becoming pregnant. It sounds more like you were using the "hope and pray" method rather than NFP.
A woman's body shows early signs of fertility by her cervical mucus. As soon as you notice ANY cervical mucus, you should abstain until the 4th day after you peak. Peak is established as the last day of slippery mucus before a dry-up. In STM methods, you also wait until the 4th day after a temp shift, which must meet certain specifications to qualify as a temp shift. I do Billings, not STM so I don't know those qualifications. After charting for awhile, an NFP instructor should be able to help you find extra useable days based on your own body's patterns if you're having to abstain for a longer-than-normal amount of time. FAM is similar to NFP but introduces barrier methods rather than abstention. Personally, I don't use barrier methods because they're known to break. Once mucus is present, sperm can survive in the woman's cervix for 2-5 days. So if you have sex, then have slippery mucus 4 days later you can get pregnant whether you use a condom on that slippery day or not because the sperm is still present. Also, ovulation can occur up to 2 days before or after peak day. This is why it's extremely important to follow the rules for whatever method of NFP you use. If you don't follow the rules, it's equal to skipping pills if you're using bcp. You might as well be actively trying to get pregnant. Here is more information about the science behind some of the NFP methods, as well as studies conducted on their effectiveness.
http://ccli.org/nfp/basics/effectiveness-p01.phphttp://www.woomb.org/bom/trials/index.htmlhttp://www.woomb.org/bom/science/ovarian.htmlhttp://www.creightonmodel.com/background.htmhttp://www.creightonmodel.com/ask.htm
NFP methods consist of Billings Ovulation Method (mucus-only), Creighton Method (mucus-only), Couple-to-couple league (STM), Northwest Family planning services (STM), Marquette method (similar to STM but with monitors added), Ovulation Method (mucus-only). A popular fertility awareness method is Taking Charge of Your Fertility. There are quite a few different methods because each woman is different, so the same method won't work for everybody. I strongly encourage you to get with an instructor, even a long-distance one, or to do an at-home course to really learn a method of NFP before introducing any foreign substances to you body that will disrupt it's natural functions. Please feel free to PM me if you need more resources, or help finding an instructor that will work with you!
: FYI, it has a very small does of hormone that only acts locally. It will not mess up the rest of your body like the pill did for me. I would never go back to the pill. As for the NFP methods, I find that they are best for planning pregnancies, but not for avoiding them. 
so at least I know everything is still working. Though, I had some unexplained bleeding near the beginning of the pregnancy that the OB thinks could be related to the scar tissue 
but no one can be sure... Anyway, the plan for after the birth is diaphram and condoms... possibly with a healthy dose of spermicide, but no more hormones and nothing else in my uterus!
: w/
lovin our baby
