In the past I've discussed about my Bf being the "father" to his UNbiological daughter. 
short story: he fathered his ex's daughter, (G)

My Bf and I now have our own daughter, his first biological baby. Lately i have been so hard on myself and feeling the heaviest mom guilt because I feel he ruined my first time and moments as a mom. It's not his fault of course, I made my choice being with him knowing that he's someone's fake dad. But before having my own baby, I never knew it'd be like this.