Here's my position on this. If your DH raises the issue of weaning, he's the one who needs to have substantiation for his position that breastfeeding should stop before your child decides to stop it. YOU don't need to be on the defensive. You're happy breastfeeding, your child is happy breastfeeding. If he wants to interfere in that relationship, he needs to be backed by hard science to support his position that breastfeeding should stop. Since there won't be any kind of evidence, what you're talking about is really his feelings and response to "peer pressure" regarding BFing.
So, if DH asks when you're going to wean, I'd respond with "why do you want me to wean?" Ultimately, it's going to be an emotional issue (he feels like it interferes with intimacy, doesn't want his child to be clingy, is embarrassed, etc.). But ask him if he has some medical evidence or study that supports his position that your child should be weaned by "x" date. If none, ask him why he feels that it should happen, and go from there to address his feelings.