What should I do

I feel so stupid. I don't know if this the right group for this but I really need to vent. My boyfriend who is also the father of my daughter is sneaky & likes to talk to a few girls behind my back. I got ahold of his phone like an hour ago while he was slowly falling asleep. I'm surprised he didn't hear me pick it up. But I was looking in a few messages and seen him calling a female he talked to on fb before " babe " I didn't see much cupcake shit more like side shit to keep it as like they wasn't talking but I see her begging him to cupcake on her birthday and try to make him be all lovey dovey to her and it wasn't working but I'm just like damn . We live together & I just feel like he's sneaking talking to other girls and cheating on me. I didn't even cry about it. That's how fed up I am with the bullshit. I feel like just leaving and starting over for good. This will only be our second year together & 5 months living together. I love this dude. I just don't even know what to do anymore & if I step out to leave him me and my daughter won't have anywhere to go. No one to turn to. I just don't know what to do!