Dive into your creative stream
Asgore would honestly be a huge softy towards his S/O.
Expect him to be distant in the beginning of your relationship. After all, he did lose his children and wife, then had to collect the souls of the fallen children. But if you show him patience, kindness, and forgiveness, your efforts will not be in vain. Little by little, with your help, he can learn to live with what he’s done, and move on.
When he finally accepts this, you will have a very caring partner, if not clingy. He will treat you like royalty. Cuddles, hand holding, and random cheek kisses are commonplace. If you stroke his fur, he will become putty at your hands.
He will become a huge dork if you show interest in gardening, showing you all the types he has grown.
Prepare for Flower based nicknames. He may associate you with a Sunflower, which stands for loyalty and adoration, similar to the way he adores you and your loyalty to him, staying with him through everything. He may also associate you with a Blue Iris, which stands for Faith and hope.