If indirectly suggesting sex therapy has not worked out, it is high time that you have a direct and detailed discussion about your misunderstandings in bed and explicitly mention your need to seek sex therapy as a couple. Ask your husband the source of his reluctance to get therapy. Give him the space to express his embarrassment or anxiety about the same. Learn about the benefits of sex therapy together. Sex therapy might seem intimidating or daunting as it could be something that your partner might have never considered before. Learning about the benefits together could lead to a discussion on what you both hope to achieve in therapy together.
Attend sex therapy online or over the phone! Sometimes when sex therapy happens from the comfort of your own home, it becomes easier to apply and be more open to what you have learned in therapy.
If this does not work out, you could consider getting therapy alone. The benefits you would receive from sex therapy would not be regrettable, and you would be able to use what you learn in your relationship. Your partner might get inspiration to take therapy after seeing your progress to see what you two could accomplish as a couple, to help satisfy your sexual needs.
Make the discussion about sex therapy as blameless as possible. Do not accuse your husband of being at fault. Work together as a unit to attain the sexual satisfaction you both individually and collectively desire. This would help you reach a pleasant outcome.
Couples are strongly encouraged to seek sex therapy together. Since the issue you are facing is happening within the context of your relationship, you would be more successful in making improvements to your sex life if both of you are working on it together.