NEED ADVICE PLS HELP😩

so, i'm dating this guy right? & he's everything i want/need. our relationship is perfectly fine BUT when we're not together i catch myself being a little "too" friendly with guys and flirting a little not having the intentions that i actually want the guy tho.  i'm tryna figure out why is this the case like why am i doing this so naturally knowing i have a boyf & am happy with him. please help☹️