So you want to learn to cope with his flirting?
The only way I can suggest, is to emotionally detach from him, so that it doesn't bother you.
That will also mean you don't care what he does anymore and will ultimately lead to the breakdown of your marriage.
There's no other way to cope with your husband behaving inappropriately with other women.
You could try flirting with other men, so that he knows how it feels and then he might stop, but it doesn't seem in your character.
It's almost like you asking how to cope with a man who shoves you, but doesn't go all the way to beat you up.
Why should you have to cope with this?
When my husband had a friendship with his Ex that I didn't want, he seemed reluctant to pull the plug, until I told him the only way for me to deal with it was to stop caring ... that meant I'd emotionally detach from him and ultimately, even the kids left home, I'd be seeking a divorce.
I can only not be bothered if I don't care about the person. If Joe from down the road flirts, it won't bother me because I don't care. I don't love Joe and he's not in a relationship with me.