Confused!!!!

So me and my SO have been going for 10 months and we have had sex many times already. Something I'm confused about is how do you know when you come? I know I should sorta know but I just never feel anything but myself really wet down south on/in my temple. I've heard that if you come too much your stomach hurts which I guess it's true bc it has happened to my SO but it hasn't really happened to me. Can someone help me🙈