My wife has this problem, at least she perceives it as one. We just had sex for the first time in two months. She had an affair prior to this. Anyways the act was going very well and then just before she thought she would have an orgasm, she would freeze and then didn't want to continue because she felt that she wasn't ready to have sex emotionally. This was also happening sometimes before the affair as well.
Any thoughts on this?

That is probably a very normal reaction since most women cannot separate sex from love. The worst thing you can do is to get angry at her because that will simply sabotage every hard effort of yours (one destructive act can undo up to 15 constructive acts), instead you should commend her for the effort and reassure her that you love her and that you want it ONLY when SHE wants it as well. Tell her that you want to express affection via hugs, little kisses to her face and lips BUT that you don't want her to misunderstand them as a prelude to sex. If she is like the majority of women, she will appreciate this because this is one of the major turn offs that women have against the men in their lives (this would be comparable to her showing you affection only when she wanted you to buy her something). ALWAYS be sincere when you show affection, attention or appreciation towards her.

Some women do not like to feel out of control. It is extremely vulnerable for anyone to be at climax. It also does create in women an incredible bond with the person they are with, if they are capable of that bond in the first place (though some women act more like men).

It's a matter of trust. She has to trust you intimately before she can let that happen. Not something easy to achieve.

If you are capable, show her moments of affection throughout the day, with no strings attached. Little touches, little kisses. Hold hands, even for a moment. It has to be real from you, not just something you do. This is hard for most men, but required by most women, whether they know it or not. It's the emotional connection she is missing, that will allow her to let go of her inhibition and insecurity with the orgasm.

Even then there is no guarantee that she will allow herself to be out of control in climax with you. If that happens, snuggle. I know, I know, very un-guy-like, but trust me. Even for you, if you mean it when you do it, it will help form a connection that will make it better for both of you. You don't even have to say anything, but insecurity will fill it's own silence, so loving words are good. You don't have to mention that she didn't finish, or what just happened. Just whisper those things that you love about her. Touch her softly, like easy (very easy) foreplay, only this is post-play, coming down from the high.

It will take some time. Be patient and keep it up. Maybe after a while, as things improve, you can talk about it. But that's for later. Help her feel secure in you first. She probably knows that it affects you. Let her know it's OK.

Question since you said freezing up is common have you both explored the possibility that she has some unadressed sexual issues?

It might explain many things. In addition if your marriage was suffering in this area then it was vunerable for an affair...pretty obvious...but will remain vunerable if that is not remedy.

Thanks for the comments. Sex was not a problem up until about 1 1/2 years ago. WW says affair began 6months ago but perhaps it was further back than that. Right now she just wants to have fun and talk and try to get to know each other again. She says she is uncomfortable with sex at the moment and that she needs more time.

You have to trust that she knows what she's talking about. If she wants to spend time together and get closer, do that with no expectations. Give her the time she needs.

She may want to prove to herself that your love for her goes beyond sex. Let's face it, we men think about sex constantly and when we tie our affection, attention and appreciation of our women to sex, they naturally end up questioning our love for them.

OOPS! Unfortunately it would appear the affair is still alive and WW is trying to eat cake.