I need advicee 😫

I got pregnant at 18 resulting in an early marriage, my child is now 4 and I’m 23. Me and my guy have now been together for 5 years it hasn’t been the easiest marriage there’s been a lot of fights and breakups over the years. At his point I’m starting to think that I should’ve waited instead of rushing into marriage because I’m no longer in love with him. I feel that I was too young and in “love” to notice all of the red flags at first. I recently started to have feelings for someone else, I told him about my marriage and everything and now I really want to pursue a relationship with him, he makes me feel so happy. But I’m afraid of how my husband will take the news of me no longer wanting to be with him. I don’t want to cheat or hurt anyone and for so long I’ve been trying to fix my relationship with my husband but there’s been no improvement over this past few months. I’ve decided I do not want to go into the new year with a broken marriage I rather end it and be happy. What should I do