This literally needs time and support. If you honestly trust your partner and after discussions he said you should do it when you feel you want to, you should trust in this. If you have sex out of obligation, it will lead to resentment and further sexual aversion. Sex can be a beautiful thing but only if it is consensual. Also, I think there are so many other ways to be intimate without having intercourse as such. Just try step by step and not by putting as a goal having sexual intercourse. Try being intimate with him and making him feel wanted as well.