I am wondering what your opinion is on self-pleasure while thinking of a spouse. It is not adultery because you are married to that person, and I am not sure if lust still applies when you are married.
I know of no argument against it other than if a person uses self-pleasure as a replacement for an actual sexual relationship with his spouse. The command, "Nevertheless, because of sexual immorality, let each man have his own wife, and let each woman have her own husband. Let the husband render to his wife the affection due her, and likewise also the wife to her husband. The wife does not have authority over her own body, but the husband does. And likewise the husband does not have authority over his own body, but the wife does" (I Corinthians 7:2-4), still needs to be met by both husband and wife.