Question about baby momma/dadies

I have a soon to be ********** son by another woman but we are no longer together and on the weekend that I have him she checks up on him and I do the same with he is with her. VERY long story short I had to take her to court for just to see my son. my current gf has 2 k**s by her pervious BF he doesn't care about then nor does he check on them to see how they are doing or anything. Her philosophy is if they aren't together then she doesn't want to see them no matter if he is taking care of his k**s or not. Here is where the problem comes into play. she gets mad saying that i shoudn't be texting some random women when im with her. (1) she isn't some ramdon female we have a k**(2) the only reason that we even keep in touch is because of our son. They went to the beach this past week because they were on spring break and his mom texted me pics of my son the beach and other pics of him. And my gf got mad at me because I texted her back asking his how my son was doing and told her to tell him i said hey. Keep in mind his mom d**g my name through the mud and other stuff and i forgave her and her family because life is too short to hold grudges. I want yall's opinion from the men/women if im wrong or not? And i will be the first person to admit when im wrong if im wrong