You can start having sex again whenever you feel ready after your baby is born. Most women feel sore and tired for a while after giving birth, this is normal and you should not feel pressure to do anything you are not up to. Most couples will start having sex again by 3 months.
Women who have small tears will need 2 weeks to heal, those who have had a cut or larger tear will need at least 4 weeks, do not have sex if you feel you are still healing.
It is good to have some lubricant when you start having sexagain as there can be changes in your vagina. Be gentle when having sex for the first time, if sex is painful speak to your GP. It is good to talk to your partner about your feelings about having sex again and any pain you have.
Remember you can fall pregnant again as soon as 3 weeks after birth, if you have not started contraception then condoms should be used until you can see a doctor or sexual health clinic.