I think a healthy approach is to recognize that habits can be hard to break and people slip up from time to time, and that’s a normal part of the process of reaching your goals and changing your habits. Do your best, recognize if you’re slipping towards an old habit. If you catch yourself partway through touching your clit, stop yourself. If you do end up touching your clit or using it to orgasm, own up to it, think about whether it was worth it, and dive back in to not using it going forward, trying to last longer without it the next time. If you and your husband have the sort of dynamic this would be appropriate for, you can come up with punishments that you feel are appropriate for touching your clit.
That said, there are things you can do to help. Focus on anal stimulation instead. Wear a butt plug often, use your fingers and a dildo to masturbate anally, and any time you feel the urge to touch your clit, play with your ass instead. If you get that urge while playing with your ass, play harder. Fuck a toy deeper or go to a bigger size, etc., and use it to motivate you to chase anal pleasure instead.
You can also experiment with numbing cream/gel like Orajel if you really find it hard to resist. A small amount applied to your clit will numb it for an hour or so.
Congratulations on getting back into the anal only lifestyle, it sounds like it’s exactly the right thing for the both of you!