Relationship advice

I need some advice. I'm not a very smart person. In fact, I'm downright dumb. I accept that. I say that because I am 38 years old, in an unmarried 23 year-long relationship with the father of my 2 kids, who I met when we were 16, I was raised by an alcoholic woman, and haven't had much experience out in the "real world", because I'm an akward, socially-phobic introvert and have always been taken advantage of by others. How do I know this? Because I am also an INFP, and I very much go by my intuitions and and gut feelings. I need advice on how to go forward with the direction of life. My predicament is my SO. I suspect he may be a narcissist, though I have no medical diagnosis to go by, but I can tell whether or not he's telling me a story or the truth, for the most part. I've seen text messages on his phone to another woman that point to blatant obvious infidelity, as in the literal appreciation of orgasmic abilities.. or, "you should cum like that every time, that was magical" Or, "Want to get a hotel room and some food?". I confronted him and he totally denied it, didn't want to hear another peep of anything else relating to him doing anything, he's completely innocent. But I've also, in the past, seen texts from him to this woman. But they weren't, or didn't seem to be, sexual in nature. I've also seen text messages between him and a different woman that were sexual, as in the woman was telling him that her husband was trying to check "down there" to see if she hadn't been "doing anything with anyone", but I didn't act on seeing this, I was actually still in shock over figuring out how to unlock the pattern lock on his phone. Yes, I understand that a person's phone is private, but in a relationship people usually ( I assume..) have discussions about such things, as in, "Hey I'm putting a lock on my phone because _____", or " I don't want you to be able to see who I'm talking to on my phone because _____", or you know, I don't know what I'm talking about, as usual. I can't have a lock on the phone I have, since he's the one who bought it, along with everything else in the apartment he pays for because I no longer have a job and can't get hired to save my life, and still actively looking, but I don't have anything to hide from him, anyway.. I worked for 8 straight years overnights but got fired for too may absences due to the fact that I've never had a driver's license and am not "allowed" to have friends. We've been together for almost 24 years and I feel like I barely know him at all. At one point I thought I did, but then out of nowhere he blindsided me with the fact that he was doing drugs and of course I wanted to do them, too.. sadly. So he started selling them, or had been, I can't say for sure, and I had no say, still don't, on anything he did then or now. After that I found out he has a very, very short fiery temper and wouldn't hesitate to physically remedy any problems I, or anyone else, introduced him with. Yes, I stayed with him. Yes, because I have feelings for him, am in love with him. Yes, I know how that makes me look. I certainly know how it makes me feel.. I don't have anyone but him, I left any family I ever had at the age of barely 17 years old. I definitely don't have anyone else now. I don't even want to leave him. I guess I'm honestly just looking for confirmation of.. idk what, tbh.. I'd really like to extract vengeance. To have him feel the exact way I feel and have felt because of him. When I was 34 I had to have all, every single one, of my teeth pulled because of health problems. And no money or insurance to pay for dentist appointments. Barely have dentures because they got broke and I had to super glue them, can't get new ones.. I feel so extremely ugly and so unworthy of love. Wear glasses. Never get to have anyone cut my hair, I have to myself. I don't feel attractive to him at all anymore. He barely touches me at all anymore. I don't know what to do with myself. I have to be a completely fake person, to myself and kids, in front of him. I absolutely hate fakeness, I abhorr it, and I'm exhausted from living it. I know if I didn't have my babies I'd have already have done away with myself. These kids are really all I have left in this world. So I can't kill myself. I just don't know what to do...