Pain During Sex?

i had sex for the first time about a year and a half ago, and it was gainful but i also assumed it would go away gradually. it’s stayed consistent and feels like it’s hitting my stomach? i don’t know how else to really describe it. it’s made me not want to do it and i feel like it’s hurting my partner and i’s relationship because i try t avoid it since it’s painful. has this happened to anybody else? i’d appreciate any advice!