4) “My EX was so much better than you!”
How many of us liked being compared to other kids by parents? Yes, none of us. Similarly, your partner will never accept being compared to your EX, especially as they may already be a little insecure about that. Making the statement the other way round is also not a good idea; i.e., telling your current partner that they’re better than your EX. While they may take it with a smile at face value, they may wonder why you are still thinking about your ex-partner. Every relationship is different and every person is different. If you find something problematic about your partner, address that specifically.