I actually understand where you're coming from, as controversial as it sounds. I've been in your shoes, and at the time it seemed easier to be the one dumped than the one doing the dumping. If you want to contact me off-forum, please feel free.
Before undertaking a classic break-up spell, which will cause major drama and hardship in your marriage (there are no clean break-ups through spells; much emotional damage and fighting ensue), google the phrase "honey jar spell." These spells work to sweeten a person, in your case to sweeten your husband to another woman *who is a better fit for him, his soulmate*. Do this work with love and compassion, wanting what's best for him, seeing him with a partner that meets his every need. You are in essence doing a love spell for him.
People may worry about the coercive nature of love spells and the morally-ambiguous nature of this particular working, but i do think it's a better fit than a break-up spell. You are the one who has to live with yourself, and after prayerful consideration you believe this is the right avenue, then as God wills it.
I would also suggest working with a pair of Lodestones on his behalf, one that represents him and one that represents his perfect future mate. Here's a working from my blog:
And another article:
May you find happiness.