girls.. i need help no judgment pls

i am going to try to make this as short and possible and do not judge. normally i would too but you never know when you may find yourself in these situations. my husband and i have been married for 2 years. we are young i’m 20 he’s 22. we have a daughters hat is 1.. before we got married he cheated on me with his cousin ( it’s his moms sister step daughter but still!) the worst part about it is she was 12 or 13 at the time and he was 20.. he says they didn’t do anything but they talked sexually to each other through snapchat. i chose to forgive him and marry him anyways now that we have a daughter it creeps me out that he talked to his 12 year old cousin like that!!! maybe it’s my motherly instincts but still. well i’ve been battling this quietly for months bc i don’t want to bring it back up but recently my husband has become friends with a guy i use to talk to before i knew him. we were in love with each other but things didn’t work out for us to be with each other in the past and we left with feelings still for each other. now that he’s been hanging out with him all these feelings have came back and just talking to him has made me happier than i have been in a while since all the stuff my husband has done has been bothering me for months. this guy says he loves me still and loves my daughter just as much and he wants to take care of us and give me what i deserve.. my husband had notified things have changed and has been a lot nicer. girls i don’t know what to do.. it’s just crazy how god has brought this man back into my life after all these years and we have no bad blood from the past .. advice?? should i stay with my husband although i don’t think i’ll ever be able to get over what he has done or should i take a leap and leave my husband for a new start???