Hi Fella. I'm in the same situation. 2 kids under 3. my wife was just getting horny after our daughter turned 1, caught on the first time . . . my son is 2 weeks shy of 2 years younger than my daughter and i've had sex with her maybe 10 times since she got pregnant with my daughter in Jan 2013. We've been to marriage counselling, she's acknowledging that there are a number of issues she needs to work on.
Porn is my outlet and release.
Talk to her. let her know your frustrations, but not that you've thought about going elsewhere. lol. Be a great dad and loving husband. It will come back, but the dynamic of your relationship has changed and you have a child that is likely to take up every waking moment. being selfish is normal, it's human. but you've gotta step back and see the bigger picture.
but, if you truly feel that the lack of sex is breaking the relationship up, then you need to be honest about that too. tell her that her not wanting to have sex with you is feeling like rejection.