I'm going to regret this, because I really can't be a regular poster and follow-up much, but here goes...
"I will second guess myself if I broke it off because of the sex issue."
The above statement sounds ambivalent about your own values regarding the importance of sex. You have to be clear with yourself about your values regarding sex before you will ever be clear with her. Is it a dealbreaker or not? Postpone your marriage and any conversation about sex until you're clear on your values. Let her know you need some time to get clear on how you feel about the role of sex in marriage. Once you're clear and okay with your own values then you're ready to have a straightforward, honest conversation with your intended.
1. Make this statement to her: "Sex is important to me. I would like to have it every day, but I'm good with 2 to 3 times per week. I feel like I'm in prison without it at that level. My values on the importance of sex are not going to change. You have communicated to me that sex is not as important to you. I understand that and I'm not going to try to change your values about sex. However, we need to work out how we're going to deal with this difference in values satisfactorily for both of us if we are to be married."
2. Redirect your own and her attempts at trying to change the other's values. This is an unfruitful activity. Focus your conversation on how to deal with the behavioral differences. The SSM book may be helpful in talking about desire before arousal and arousal before desire and how to go about having sex when you don't really feel like it. But first you have to agree to accept the value differences and be okay with one another regarding this difference. (One of the messages that I took away from the SSM that helped me as someone who really likes sex, is that it is perfectly okay for sex not to be that important. Don't worry, Michelle also tells the LD partner they need to consider the values of the "HD" spouse.)
3. You, she, or both of you may decide that you can't work out this difference. You can still love each other, but you'll need to find others with whom you are more compatible to be marriage partners. Neither one of you is wrong. You're just different and you can't work out the differences. A painful, sad situation for which you both may grieve.
4. Once you are honest about how important sex is to you, that it is a dealbreaker, then and only then will you know where you stand with her. It is possible that her view on the value of sex is as much a dealbreaker for her as it is for you. But you both have to be honest with one another about this. Otherwise, how can you possibly say that you want to be married to each other when you don't really know how strong each other's values are on this important issue. If you haven't postponed the engagement over this issue yet, then she doesn't know how strongly you feel no matter how much you think you've told her.
5. No one has to be wrong, or labeled negatively, or have issues. You may just have a difference in values that you have to work out...or decide you can't. It might be painful and result in your parting ways or it might result in a much better relationship and better understanding about good communication. Be clear and honest about where you stand and okay with where you stand.
P.S. Be clear with yourself also on whether you need her values to be the same as yours regarding sex or whether you are okay with working out the behavioral differences. If you need her to need sex the same way you do or for it to mean the same thing to her, then you have a harder task because then you *do* have to try to convince her to share your viewpoint regarding sex. So be very clear about what you really need from her.
