I would definitely follow illyriums advice.
I would also find out why he is feeling this resentment. That would be the key to the problem. You need to know the source of a problem before successfully treating it. Just like an illness, if you only treat the symptoms, the illness itself is not addressed or healed. Emotions are the same way. Just removing his resentment will only be a bandaid that will work temporarily until the cause manifests in a new way.
Once you find out the "why?" concerning his resentment, the solution may be totally simple. Perhaps it's something you do that you're not aware of. It's important not to become defensive when he answers why he feels this resentment. Understand that these are his emotions and he is sharing (which is good). Instead of becoming defensive, instead ask "what can we do to resolve this?" Listen openly.
Magick can be used to help the two of you to be more flexible and positive. But the spell should be on BOTH. If he is feeling resentment, he is not "the problem", whatever is causing this resentment is. A good relationship is not about one or the other getting their way, but about compromise and working together to solve problems.