Whatever form of birth control you use, make sure you get LOTS of foreplay! That will help him enter you easier, you'll enjoy it more, and it might not hurt as much.

DO NOT use any kind of oil-based lubricant (such as Vaseline) with the condom; only use water-based lubricants. Oil-based ones can weaken the rubber of the condom, and that will kind of defeat the purpose.

Here's one more method of birth control, but I doubt you'll want to use it, since you need to get pregnant first :

Lactational Amenorrhoea Method (LAM)

Women who are breast feeding exclusively may be protected against pregnancy for up to 6 months after the birth if her period has not returned. This method is highly effective when used correctly. LAM works by preventing an egg from being released from your ovary. Once you begin to feed your baby food other than breast milk, or when your period returns you need to choose another method of birth control.