Remember, this pregnancy is a major event in your partner's life, too. Odds are, his seeming lack of interest has nothing to do with how he feels about you. Fear and anxiety about starting a family and being a father (gulp!) may be causing him to take a step back. And, what with your swinging moods (don’t deny it!) and shifting hormones, he may be nervous about how you'll react (physically and emotionally) to sex.
Another possibility is that he’s tentative towards intercourse due to fear of hurting the baby. If this is the case, remind him that baby won't feel a thing, and if he doesn’t believe you, drag him to your next OB visit and let her do the talking. It also might be be that your husband is uncomfortable having sex “in front” of his child. Sounds crazy, perhaps... But who says this is a rational time?
Whatever the case, open lines of communication are essential. Being honest about your own needs and fears will encourage him to do the same. If the truth is hard to hear — even the most loving, devoted husbands can find intimacy tough during pregnancy — remember that this is a strange journey for both of you. Just like you, he's doing his best. And, don't forget about other ways to stay connected. Back massages, foot rubs, holding hands, and kissing and cuddling can be just as romantic as anything else.