Hello Kavindra, seems like you're just anxious about sex. Don't be. When you are with a partner, focus on open communication and try to explore and learn things together. Later if needed, you can consult a sex therapist who can talk to you about specific concerns, should they arise.

See sexual life after marriage has its own impact on your as well as your wife's sexual desires along with satisfaction and if any one of you is unhappy with your sexual life than this is the main reason or cause whatever you say for extra marital affairs. With regard to your query any time is safe for doing sex if both partners are willing and doing it with taking precautions like using condom or taking post coital pills soon after having intercourse. In other words if you are not willing to use any precaution than it is almost safe to do sex between first 7-8 days and than between 22nd to rest of your partner's menstrual cycle period.