For the time being you can set up new boundaries between the two of you.
Maybe she DOESN'T want to hear about your love life. You don't know yet. You have to find out
You might be looking for his validation and encouragement because you believe that's what a good friend should do.
Now, it's very much possible that when you share the feelings you experience for someone else, he might not like it.
The best way to find out is to share some light flirting anecdotes and see how he responds.
That's a good way to test the waters.
You can say for instance.
"I love this spring feeling. All these guys looking so sexy! - I was in town having a drink with my friend and this guy at the table next to us was definitely checking me out - He was cute, we chatted a bit. He just moved into town..."
While you share something along that line, observe your ex's emotional response. Is he enjoying hearing your story or does he resent you sharing that?
It's essential to know.
If he resents it, it means you should not share your love life with him unless he asks you.
This means that if you support his love life (listening like a good friend) but he doesn't support yours, it can create a strong imbalance in the friendship and you end up frustrated.
We can check what to do once you know more about his response. That will be for another tip.
If he likes it, gets excited, asks you follow up questions, it means that you can establish now a new level of complicity right there.
Try sharing your love life the way I described above and see how he responds.
Just talk about you dating or flirting in general
How does he respond when he envisions you with other men?
Does he like it or not?
Test it! You will quickly get an answer!