Visit StorkNet's Pregnancy Discomforts page for remedies that helped other parents. Many women go through a change in their desires during the first trimester. Mom may feel so crummy with morning sickness that she won't even let you in the bedroom. On the other hand, without the hassles and worries of birth control and with the surge of hormones, she may be a sexual maniac. In either case, she's normal.
Dads can also experience a change.
The figure changes may be quite attractive to you, and you may feel like a 16-year old boy again. But, you may be worried about hurting the baby or doing something to disrupt the pregnancy. If mom isn't on the same wavelength you are, this can be tough. Be understanding and remember that her hormones can make her moods look like a yo-yo in perpetual motion. If you're both in the mood, enjoy it.