、。、。
My husband has two older brothers. Yes, I married into the third-son role.
Literal
My husband [to-には], older-brothers [subject-が] 2-[counter-人] exist-[polite-います]. Yes, I [topic-は] 3rd-son [attributive-の] bride is-[polite-です].
A short, loaded cultural sentence. 三男の嫁 ('the wife of the third son') is culturally significant — in traditional Japanese family structure, the eldest son (長男) is expected to carry on the family line and care for aging parents, while younger sons and their wives have less of that burden. The speaker is explaining, with perhaps a touch of wry relief, that as the wife of the third son she is comparatively free of those obligations. 嫁 specifically means 'bride, wife-married-in' — emphasizing the in-law dynamic.