Hello, I'd like to help you with your question.
The problem you describe can be a sex therapy issue. It depends very much on why your husband is having an affair and why he feels he cannot express sexual feelings towards you and also if this has been a long standing problem throughout your marriage or a recent one. Because of your husband's behavior and his feelings about your marriage and you, therapy for him is vital as a first step.
Depending on your past sexual relationship with your husband, the therapist may need to explore why your husband had the affair and the root cause of the affair. Infidelity is never the other person's fault in a marriage. Instead it often points to an issue with the person having the affair. For the person having the affair and sexual issues, the behavior can stem from past experiences or from personality problems. They can also be caused by the spouses inability to cope with their own feelings.
You have a choice in deciding if you feel the need to go to therapy with your husband initially or tell him to go on his own. As I mentioned, the problem in the marriage seems to stem from his behavior, not yours. So therapy needs to start with him so he can get to the root cause. You can also have marriage therapy together to heal the damage done to your marriage because of the affair and your husband's feelings about sex in your marriage. While sex therapy can be part of the overall therapy you receive, it is more likely that whatever is causing your husband's behavior is more complicated than just sexual issues.
I hope this has helped you,
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