It could be an issue of technique, especially if your wife cums more from clit stimulation than penetration.
On the other hand, there is a big psychological component to having an orgasm and anxiety or just any sort of thoughts going through her head could distract and cause her to become disconnected from what's going on with her body. It would be natural to worry about what a new partner is thinking / feeling, feeling self-conscious, etc. Also just the fact that sex with someone other than your husband is taboo and not socially acceptable can create conflicting feelings of arousal and excitement but at the same time guilt and uneasiness that makes it harder to fully enjoy the moment. Even as much assurance as you give her, there may still be worry about about how you're feeling and whether she is doing the right thing.
It's an emotionally complex situation. While the excitement of this new sharing situation is probably quite high for her, it may take a while for her to feel fully comfortable with what she's doing. It may also take a repeat lover that she can get accustomed to, who knows what she needs. I'm sure she'll get there eventually.
Like you suggested - foreplay would probably help as it helps everyone relax and mentally get into the experience.
On the other hand, there is a big psychological component to having an orgasm and anxiety or just any sort of thoughts going through her head could distract and cause her to become disconnected from what's going on with her body. It would be natural to worry about what a new partner is thinking / feeling, feeling self-conscious, etc. Also just the fact that sex with someone other than your husband is taboo and not socially acceptable can create conflicting feelings of arousal and excitement but at the same time guilt and uneasiness that makes it harder to fully enjoy the moment. Even as much assurance as you give her, there may still be worry about about how you're feeling and whether she is doing the right thing.
It's an emotionally complex situation. While the excitement of this new sharing situation is probably quite high for her, it may take a while for her to feel fully comfortable with what she's doing. It may also take a repeat lover that she can get accustomed to, who knows what she needs. I'm sure she'll get there eventually.
Like you suggested - foreplay would probably help as it helps everyone relax and mentally get into the experience.