My Fiance and I have been having sexually active for about a year now, but we don't live together so we don't get to have sex that often, usually only on weekends if we're lucky and get my house to ourselves. We don't use condoms because the latex makes me break out and I haven't started birth control yet because I wasn't sure about what to use and because since both of us are Christian, we thought that if I got on birth control we would have sex more frequently which we didn't want to do since we were trying to keep from doing it too much and thus getting pregnant. Whenever we have sex he pulls it out before he ejaculates, but I've heard that some people still can get pregnant when doing that...is this true? Also, I'm really worried about gaining a lot of weight when I start birth control, because weight is a very big issue for me...is there a birth control that I can use that is effective, but won't cause me to gain a ton of weight?
Right now, it sounds like you are your partner are practicing withdrawal as a form of birth control. As a method of contraception, withdrawal is not the most effective choice available. With perfect use it is about 96% effective (meaning that about 4 out of every 100 women using it will become pregnant in a given year), the typical use rate is about 73% effective (meaning that about 27 out of every 100 women will become pregnant each year). One of the reasons that withdrawal is not typically a good first choice method is that it is very hard to practice perfectly. The man must withdraw completely prior to ejaculation every time. Sometimes it can be difficult to pull out in time, or ejaculation may begin before the man realizes (orgasm and ejaculation are not the same thing and can happen separately). Also, we know that pre-ejaculate (which can be released at any point during an erection) can contain sperm that may have been left over from previous ejaculations. This risk is believed to be reduced by urinating prior to contact. Also, withdrawal does not provide any protection against STIs. We generally recommend full barrier use with new partners and each of you testing clear twice before considering the risk reduced significantly enough to stop using barriers. Also, you'll both want to continue getting annual testing.
So in general, if you and your partner are wanting to avoid pregnancy, it would be really wise to consider other contraceptive options that offer better pregnancy protection and also can help prevent STI transmission.
You mention that latex causes you to break out, you may want to explore that further. Do you always notice rashes when you are in contact with latex? For example, does wearing a latex glove cause you to break out? If so, then you may have a latex sensitivity or allergy. Luckily, there are excellent non-latex condom options available. Polyurethane (Avanti, Supra, the Reality female condom) or polyisoprene (Skyn) condoms are readily available for those who can't use or don't like latex. If you are only noticing this reaction with the condoms and not with other latex (like medical gloves or certain bandaids), then you may be reacting to something else. Are you using condoms that are spermicidal or have a "special" lube on them? Or if you are using extra, bottled lube, is that spermicidal or numbing/cooling/warming/tingling/etc.? If so, then you may be reacting to something in the lubricant. The easiest way to solve this is to either go with something that has a plain, condom-safe lubricant. We have several articles about condoms that you might want to take a look at:
There are many methods of birth control available that you can choose from. You may want to start with our article Birth Control Bingo. It can help walk you through the different methods so that you can find something that is in line with your lifestyle and needs. No method, aside from abstaining completely from activities that create risk, is going to give you 100% protection. However, backing up with a second method can add additional protection and reduce your risk further. Our article The Buddy System: Effectiveness Rates for Backing Up Your Birth Control With a Second Method will give you some idea of how effective different methods can be when paired together.
You mention being concerned about gaining weight with hormonal contraceptives, which can be one of the relatively common side effects. However, do keep in mind that we are generally talking about something like 5 lbs here (and generally it is from water retention) and that it does not happen for all women. Not everybody gains weight, nor is it always related to the birth control itself. For example, we may be at a point in our lives where our bodies are changing anyway. Or maybe we are altering eating or exercise habits. So this may not be as big an issue as you imagine. If you do find that you have weight changes or other side effects that you don't like, you can try a different hormonal formulation or a non-hormonal method (like a diaphram, cervical cap, or Lea's Shield).
There is nothing inherent about using a method of birth control that will cause anyone to have more sex. You get to make choices about how much sex (of any sort) that you have. If you are not comfortable with a given amount of sex or a certain level of risk, then you simply choose to abstain from those things. From your post, I get the sense that you think that the more sex you have, the more likely you are to become pregnant. But at the same time, you are currently having sex using a contraceptive method that has one of the highest failure rates. Unreliable methods (or no methods at all), whether you are having a lot of sex or only a little sex, can definitely lead to pregnancy. If you cannot find a method that gives you a level of protection you are comfortable with or if you and your partner do not feel okay about being sexually active, then you absolutely can choose to abstain until you are more comfortable.
Here are a few other articles you may want to take a look at: