Overall, this is beautiful. Showing us how much he means to you.
Vision: The picture clearly shows how you feel about your relationship with your boyfriend. The idea is good, I think adding the sunset in was a lovely idea.
Originality: I haven't really seen this type of drawing style from you before. But I think it's wonderful and maybe you should a bit more. I don't think I see many fursona couple pictures were the Ocs are like this, from it's angle etc. So great job on making something original!
Technique: I can clearly see a good technique being used here. I love the idea of it. The grass looks lovely. You how shown were the water is flowing from. However, I would suggest you blend the water meeting with the grass more, maybe make it a bit more muddy? To really show the effects when the water touches the grassland. I would also say, bend the bridge in more with the grass to, however I'm not sure how to explain how to, sorry.
Impact: Overall, it's gives off a great impact. From your other pieces, we can all clearly you love him and him alone, you want to keep him, treasure him forever. I think this is a wonderful piece, one of the best from you.
Keep up your hard work! c: