People are trying to help you by pointing out that there is a connection between your laxity in boundaries with your friend and her boyfriend, and your lax attitude about how you present yourself. This "I don't care" lax attitude tends to spread from one area of an individual's life to another. Both contain a lack of consideration for others and come off as lazy and inconsiderate, as well as immature.
The situation you created cannot be repaired. The best you can do is leave the family alone and hope they sort through it so this child can have a two-parent family.
What you can do though is work on your sense of respect and discipline for yourself and others.
I am a parent and you know, when I was teaching my son certain habits like making his bed, it really wasn't only about wanting the bed made. I wanted him to grow up with self-discipline to do what needs doing. I wanted him to grow up expecting to live in a pleasant atmosphere. When I taught him how to act toward others, including people he or I didn't like too much, I was trying to also teach him what to expect. While I wanted him to learn not to two-time his girlfriends, I also wanted him to learn not to tolerate if his girlfriend acted badly toward him and to move on.
These things all go together - if you don't care how you present yourself (such as with poor grammar), you don't care what others think of you. Well, you won't get far in life with that attitude. If others don't think well of you, you can expect only other disrespectful, lazy people to want to be around you and they are going to be lazy and disrespectful in their relationship with you.
You may see this indiscretion as one incident. I think some of us see it as an indication that you lack respect for yourself and others, and lack self-control (discipline). We are seeing an additional indication of this in how you represent yourself from your "I don't care" remarks to your grammar, and we're trying to help you by suggesting that you start being more attentive to these apparent habits.
You asked for help - we're glad to give it but the thing is, you don't want to hear the truth. Deflect and ignore it and devalue it, and expect more of the same ruined relationships moving forward. It doesn't impact us - we're just trying to help you.