Sh0ckìng Moment, 5-Year-Old Girl Was Cónfirmed Prégnant (Photos)

Pls your advice is needed.

I have been dating this girl since school days from ND to HND, we started living together when we were in HND, after graduation i decided to go do introduction so we can make things official.unknowing to me she is two weeks pregnant for another man and she kept silent. We were planning to do our traditional marriage and she didnt say anything, one faithful day her phone was with me when a guy sent a message to her saying how missed the way they made love and sent a photo of both of them n*ked. I got to know she was pregnant when the same guy was asking her when she will breakup with me so both of them can marry and have the child together. I have not confronted her yet about it, i have been dealing with dëpression because i have invested so much on this girl since school days. I love her so much and i am in the verge of taking my lïfe.. Please i don't know what to do. The traditional marriage is in June. Should i confront her or just walk away?