I want someone else...

my fiance and i have not been connecting like we use too.... we havent been connecting at all. the sex is bad. we barely show affection to one another and barely talk anymore. when we do talk we just fight we have 2 children together a 4 yr old and a 4 month old and he never spends more time with them or us than he has too... i have been helping my parents this last week because my mom is in texas for work and from friday-today we have barely spoken to each other... There is this guy i work with that i have been talking too just as friends for a few months basically we just vent about our shitty relationships and give each other advice... i started having feelings for him and i told him yesterday about how i was feeling and he feels the same way... actually his feelings are a bit stronger than mine. all day i have been thinking about my relationship with my fiance and i realized we havent been connecting for a while... the last time we did anything together was Valentine's day... other than that its been him going out and me alone at home. we always fight about our relationship our connection and just not knowing what we are doing anymore. I love my fiance but 95% of the time i feel like im alone. and i tell him this things change for a few days and then back to normal. my coworker wants to take a chance with me and idk what to think. i really like him and we have a strong connection but i have 2 kids with my fiance and idk if im willing to risk my fiance for someone that might work.