After giving birth, there is no 'right' time to begin having sex again - you may be ready again within a few days, weeks or it may take months. You might want to wait until your bleeding has tapered and any sutures or tears from the birth are healed. You may have questions about the timing and safety of starting sex again, pain during sex, changes in natural lubrication, breast/chest tenderness and changes in libido.
If you're having sex with a male partner, it's important to consider contraception before having sex as you can get pregnant within weeks of giving birth, even if you are nursing, and even before your period has resumed. There are many other ways to experience intimacy with your partner other than sex if you do not feel up to it at this time. See the sources below for questions and answers on all these topics as well as information on pregnancy spacing.