All Shinta wants is to find a girlfriend, and constantly falls in 'love at first sight' with his classmates. Unfortunately for the boy, none seem to reciprocate his intense feelings, and thus, he does the only thing he can think of – he visits a local shrine to hopefully have his wish granted. Much to his surprise, Shinta encounters a god at the shrine who decides to grant his wish, and the next morning, Shinta wakes up next to the lovely goddess Isana. But all wishes come at a price – it's that time of year when gods throughout the world battle it out for territory, and each deity like Isana must use a human as their champion. Now, Shinta must fight countless enemies for his newfound girlfriend, even though she doesn't seem to want to give him the time of day!
Both of those series feature a male lead who confessed to many girls without any success and who by chance finds himself a girlfriend who is (way) more than he ever bargained for. Because of this and other reasons, those two manga do feel similar, so if you liked one of them, you might like the other one as well.
I can't really point out the similarities between those two (other than the male lead fighting using a very unique weapon), but something reminded me of GAN☆KON when I was reading Tsugumomo. Anyway, it's just a hunch, but you might like one of those two if you liked the other one.
P.S. Tsugumomo can be very crude at times.