Can you change a flirt? No you can’t. But keep reading, there is still hope for the situation.
If the one you are in love with is a flirt, don’t expect that once you’re married, you will be able to change him or her. It doesn’t work that way. Acting jealous won’t make them change. Giving them a taste of their own medicine is also not a good idea. It usually ends up creating even more problems. So does that mean there is nothing you can do? Basically yes. You can’t change them. The only solution is if they want to change.
Can a flirt change? That’s entirely a different question. Yes,they can. But it has to come from them. They have to want to change. They need a reason to change basically.
Often this may happen when they really fall in love and settle into a serious relationship. Then the flirting might simply fade away because there is no longer any need to and because they are committed. I know it can happen. I’ve known cases where exactly that has happened, once they found the right person and seriously fell in love and committed to that person, the flirting stopped.
If it does not change, instead of getting in a sulk or issuing ultimatums or overreacting, one of the things that might be helpful is to talk to them and tell them how it hurts you to see them flirting with someone else. Once they realize what they are doing is hurtful, it may give them the incentive to change.
Of course sometimes what jealous spouses see as flirting is not at all. I’ve known people who overreact and become jealous,suspicious and accusatory, or become whining and clingy, because they believe their loved one is flirting, when the outsider can see the person in question is not flirting at all. In reality it is only a natural friendliness and nothing more. The problem is not with their partner but with them and a suspicious, jealous and insecure nature.
So before you overreact, you need to determine if they really are flirting or just being naturally friendly. Or whether it is you and your attitudes that need to change.