Am I with a narcissist?

Hello I have been in a relation with my partner for 9 years we live together and have children I am 29 and he’s 31 so the past couple months have been very hard let me just jump straight in make a long story short I found out that he’s been living a double life and has another family the child is 2 years old I knew nothing of this until I went in his car glove compartment and found a birth certificate that does not belong to our children or me with his name listed as the father I broke my heart I held onto the info for days not knowing what to do seeing my life change before my eyes looking at my children it’s painful he held this secret for 2 years the child is 2 years old I’m crushed I have been honest and faithful this entire relationship I feel cheated and very upset so we get into a argument and I bring it up because he’s speaking so highly of himself as if he’s not living a double life it triggered me so I brought it up and expose it he gets into rage and curse me asking why am I plundering through his things gets very upset with me for finding out them saying I’m glad the truth is out and now I’m going to be getting the child and they will be getting to know our kids no apology nothing storms out the house so weeks went past we get into another argument he disrespects my mom bringing her up for no reason to get under my skin infront of our children so I say that it I’m done get your stuff and leave he saying he been wanting to leave he’s over me so on as if I have done anything to him so we aren’t speaking he’s clearly disrespecting my mom and doesn’t even care so we aren’t speaking again for days and I start answering old friends that’s in my messenger on social media and all I’m talking about in the convos is about what I’m going thru at home how I can’t believe my partner of 9 years is living a double life the next morning he sneaks in my phone and see the messages and flip everything on me call me all kinds of names say I’m not with and will never be a wife I’m sneaky I’m a snake all the worst names I just need opinions of this situation is this gaslighting me I know I wasn’t supposed to be telling people out business but he doesn’t talk to me for weeks at a time and does it often acts as if I don’t exist I felt like I needed someone to talk to and to tell what’s going on