No need to stop sexual activities unless you have a history of previous abortion or premature labor. It is advised to decrease it in the first 3 month where the gestational sac is not yet stable and in the last month as the seminal fluid has elements which cause contractions and might induce premature labor. Sex should be gentle and not rough, using positions which doesn’t add pressure on the abdomen. Some women feel disgusted from having sex during pregnancy because of her hormones or nausea or discharges while on the other hand other women have a more powerful sexual drive in pregnancy.