If you suspect your signifigant other might be using a dating site or app, there are a few ways to confirm your suspicions.
You'll need to check their phone for common dating apps, conduct a Google search using personal details like their email address, and, if necesary, create test accounts on popular apps and sites to see if your signifigant other is returned as a potential match.
Because whereas a woman will link certain events in her life together, preferring to see these events and situations as somehow related, struggling to understand how an ex-partner's behaviour isn't a reaction or a result of something she has done (when he says it's not you, it's him - take heed) a man will close the old box and open the new one. Woman's brain - "I don't want to date too soon after we've broken up, it undermines what I had with my ex and I should have some time on my own to grieve over our failed relationship.
Besides, I'm worried that if I launch into a new relationship quickly it might have an impact on my ability to commit in the future." Or in layman's terms, your ex-boyfriend wants a shag 20 times more than you do.
I don't sit these two examples next to each other as confirmation of women's madness, hell no, they'll be world peace before that list was finished, but as example of something totally unchangeable - men and woman are different - always have been, always will be. There are endless scientific studies proving that there a countless differences in the male and female brain. My friend was confused as to how her relationship had meant so little that he could be back out so soon after the split, she had absolutely no reason to be.
Scaring/harassing the new girl away is not going to help.
I always welcome constructive criticism and was glad that my writing had stirred up passion in his loins, albeit of the confrontational sort. In fact it was only a few days ago that a lover told me that the reason he enjoyed my company so much was that I was 'chaotic, unpredictable and totally unsuitable as a girlfriend' - a compliment if there ever was one.
I would far rather be called mad and chaotic than nice and safe ...
Exception: There is one exception to this case and that is if you and your ex boyfriend had been dating for a very short time (like a month or two weeks).
In this case, since your relationship wasn’t very strong in the first place, he is not technically with a rebound girl.
Did you know that dating other guys is one of the best ways to get your ex boyfriend to come back to you?