The time comes in many relationships to "tap it", and, as I hope you know, it is advisable first to "wrap it". That being said, there are certain deterrents-- even when they are going to have it, many people have a curiously visceral aversion to talking about sex. However, wearing a condom is extremely important, unless you are in a strictly monogamous relationship and want to have a baby/have another birth control method. When you want to bring up the condom issue, whether it's directly before you do the deed or earlier on, the bottom line is that this is your body and you make the rules-- if you want to wear a condom, don't let anybody tell you otherwise. If your partner refuses, remember that if they don't realize that you are a god/goddess/the best thing that ever happened to them, they are probably a fool and don't deserve you. You deserve somebody who respects your body and who prioritizes your safety over their own comfort. If all else fails, follow the route of this young woman:
Ladies, if he tries to tell you that sex doesn't feel as good or that condoms ruin the mood, tell him that sex doesn't feel good or romantic when it could get you sick, pregnant or both. If you have an issue with the cost, they are often free at Planned Parenthood and getfreecondoms.org. If one of you is allergic to latex, there are plenty of polyurethane condoms available. And keep in mind that there is no time of the month when you cannot get pregnant, and that even if you are taking the Pill or some such method, be very wary of STDs/STIs-- many of them often appear symptomless for a long time. Just put it on!