not my husband's baby

I'm pregnant with another man's baby. I left my husband 7 weeks ago we were arguing a lot and I felt I had fallen out of love with him. two weeks later I find out he has love bites all over him, he's been kissing and god knows what with other women. it hurt me so I went and started sleeping with another man I felt so upset I suppose it made it alright in my head for me to do it too... big mistake after being told for years I cannot have children naturally I am now pregnant with the other guys baby I am 5 weeks.. the guy knows and is so happy I am yet to tell my husband.. I want him back but I have someone else's baby growing inside of me.. I so wish it was my husband's baby...😓😢😢😢 I'm so sad. I'm sad because he is a good man that was upset with me.. and I repay him like this... what am I suppose to do. I am lost and frightened