How am i going to explain to my fiancée that am carrying my ex child?

Hello admin, my name is Joy Odey, I am from cross river state. I am a 23-year-old girl, about to marry a man i truly love.

About five years ago, i ended a quite painful relationship, and my husband-to-be helped me to get over it. We started as friends, but gradually fell in love and grew to appreciate one another. Eventually, he proposed to me and i gladly agreed to be his wife.

Our wedding’s due in November, we haven’t had sex so as to consummate our relationship on our first night together.

Although, neither I nor him are virgins, we agreed to wait until after our marriage. All was going well, until i ran into my ex about two months ago. To cut the long story short, we met up, had a few drinks and ended up in his apartment.

Recently, I found out that i’m pregnant. Neither i nor my ex want to continue our affair, and I feel terribly guilty.

The million naira question is: do I tell my fiancee of my one-night stand, or do i seduce him and make it appear the baby is his?

Please, What should i do???