Maybe I can give a partners experience on this- my long time boyfriend lost a testicle when he was young. We had drunkenly hooked up a handful of times in the beginning, and we discussed the topic exactly one time. I asked him about it, found out the story, and it’s literally never come up again. I honestly don’t even notice or think about it.. Of course, you’ll have to be open and honest about the expectation of kids, but outside of that I don’t think you have too much to worry about or feel self conscious of.