There's not enough hours in the day to cheat on her if she's sucking your dick right. Too drained to look for other mouth and pussy.
Why do you treat her like a sex toy?
Women are objects, like you would use your phone, a pen, or any other thing that is there but there's a better version of it.
Focusing on your own sexual gratification and disparaging your girl with disrespect is wrong. Women are not pens or phones to be used by you and it is up to you not to treat them that way.