The most non-superstitous of us, become cross-wielding lunatics when it comes to reproduction. We're suddenly afraid we might not be able to reproduce or think that if we tell anyone we're "trying" then we'll ruin it all. We feel its our fault, that we somehow jinxed ourselves if we tell that we're pregnant before 12,13,14 weeks if the pregnancy turns out not to be viable. Which is all nonsense. We alienate ourselves from good supports this way.
My belief is that raising children takes a village and so we have to start building our village. In order to do that, we should take apart our notions of what shouldn't be talked about.
I'm not advising that you spread your beeswax to any and everyone. I'm saying, find people you feel comfortable talking to. And start talking to them. Because here's what can happen:
You can have trouble conceiving. And that feels crappy. And it feels crappier if your girlfriend (who doesn't know you've been "trying") gets pregnant the very first month off the pill. And it feels crappier still if she's bitching about her husband wanting sex all the time when she feels like vomiting "because of the hormones" while meanwhile you and your husband are starting to feel like you're getting a reacharound from the infertility doctor every time you schedule sex.
Or none of this may happen. But keeping everything bottled up seems to make things worse. So I'm generally advising that you find friends that you can talk to. I mean really talk to. And you set shame up on the shelf for now and cultivate those relationships with all your heart. Because you all will need each other. Because even if none of this happens to you. It might happen to her.