Feeling misled

How would you feel if your boyfriend found out his ex had a baby and did the math with his mom to see if it was his kid? But he never told you and you found out thru the grapevine? I kinda feel misled bc I am currently pregnant with our child and I just feel like he should’ve communicated this with me that he might possibly have another child…idk let me know your thoughts on this.

Look he knew she was pregnant and didn’t care to do the math until after the child was born. That much I know bc he told me she was pregnant and it wasn’t his. The issue is he had to do math after the fact he said it wasn’t his baby. After the baby is born he decided to do the math. I know it’s hard to understand someone trying to explain in 3rd person on the internet…but since he said it wasn’t his from the start I took his word for it…