It does seem kinda weird to me to not be okay with having sex for 11 years but then feeling okay cheating? But I realize that you don't really feel "okay" with it. I think you may be a little harsh on yourself. It isn't really a problem unless you go through with it. It sounds like you have a natural enjoyment for sex with your husband - all of which is perfectly natural. However, 43 isn't much past a woman's sexual peak (usually around 30-35) but 56 is much past a man's sexual peak. So the differences there don't surprise me. However, I think an open conversation about it is necessary. Have you two talked about it? Have you ever told your husband that you would like it more often?