I meant to reply to this last night and forgot - sorry OP.
Early 20s, with a child and some extra weight due to said child. Is she depressed? Maybe she's hiding it from you or you can't see it, but it sounds a LOT like it to me that she's depressed. Not sure how old the child is, if it's still post partum or what.
A lot of the following is based on assumption of depression..
You tell her you love her - she doesn't believe it. After all, how could you still love her stretched out belly when you know what it looked like before?
These other online men listen to her (so she feels) because they are reading what she types. These other men tell her what she wants to hear (maybe they truly feel it or they are just saying it to get in her pants). She feels that they like her for who she is and without the obligation to say that they like her (marraige = obligation).
She's committing infidelity - period.
I know you work graveyard and she is working while you are at home with the child, but when are you spending time together? You two need to get back to spending time with each other and enjoying each other AND this beautiful child you created.
It is possible that she is addicted to this online chatting (I myself have been at times) and she just can't tear herself away from it. This IS something you can work through. It may take some time, but it can be done. You are welcome to send me a note and we can discuss this more.
We've been through this in our marriage, not the same exact thing, but something similar. I was 19 when we got married and apparently within a few hours of saying "I Do" I was expecting our first child
I know how it feels to be young with a child, hubby working long hours, etc. Fast forward - we're about to celebrate our 11th wedding anniversary and are more able to work through issues now vs our 1st wedding anniversary. Some of it comes along with life experience and maturity, no doubt, but that's not something an early 20's person tends to want to hear
I wish you guys luck! If you made it through this note - congrats
