Well, this sucks, idk.

So, thanksgiving with family went amazing today, everyone was having a good time and etc, well i noticed my fiance has been in an off set mood, like i cant really explain, he was being social but kinda just not himself, i know bc i know him and usually hes all out there, talkative and etc, and most of the time I haven't been around him bc we been spending time with our family and talking and all, and he's been on his phone, i figured usually facebook or whatever...

But anyways here a short story so his baby mama has came into the picture bc she now wants him to see his son, and its been 5 years, and they only talk on Instagram, bc he doesn't know what her full intentions are, but clearly her intentions just isn't him seeing their son and etc! Well, we get home, and i immediately charge my phone bc it was dead and I grab the tablet, and he immediately starts asking for it and I was like i wanna check my stuff, let me remind you, hes logged into his stuff on the tablet, like fb, instagram and all, and i get on it mostly to shop or check glow, well i go to instagram just to see if he's spoken to his baby mama, it showed that there was a new message but as soon as i clicked on it, it fuckin disappeared, i immediately asked him if he's spoke to her today and all, and he starts saying no, and the Last time he spoke to her was like 4 days ago, where she was just like saying, their son really wants to know him and that their son was asking her when is he (my fiance) moving back to texas, ya know, she's using their son to get to my fiance pretty much, when you read between the lines.... anyways, he just starts getting defensive and says that it told him he had a failed message when he was trying to send her message back that day they spoke but why all of a sudden would it pop up now after 4 days??? It would pop up immediately if the message failed to send, anyways I didn't believe that bs...so I know what I saw and I saw that there was a new message and then it disappeared, idk what to believe, but it's all the signs like him being all weird today his mood, then wanting the tablet as soon as we get home, and then the failed message bs, like what am I suppose to do here, he has never shown me a reason not to trust him, he's never cheated on me? But God I do not trust his baby mama, i do not trust her intentions, bc clearly her intentions is not only him seeing their son but to possibly hope for a relationship with my fiance.... either way it got me all messed up emotionally, to the point I didn't even wanna fight with him bc after that whole failed message bs i feel like he just lied to me, i need opinions here!!!

Or advice please!! What should I do? I just been crying non stop, and he just keeps saying if you don't believe me then why you staying with me, and i told him I just hurt and that whole failed message crap is bs and I know what I saw....

Can someone please give me your advice or opinions on what you think about this situation??

I hate how such a great amazing day, went to shit real quick!!

Thank you.