I was in a similar situation OP and I’m so glad I ended it.
I was 28 and he was 48, he was good looking and charismatic and a lot of my friends fancied him. He loved to do the “hot and cold thing” by chasing me and drawing me in then going cold so I’d persue him again. I think it made him feel better knowing I was so keen on him and younger.
Eventually I had enough of his games and a few months later started seeing my DP who is the same age. That was nearly 12 years ago and I’m now 40 and my ex is 60.
I hadn’t seen him for a long time but bumped into him the other day, I didn’t recognise him until DP teased me about how good my “older man” looked. DP knew him as he briefly worked with him but I hadn’t seen him in over 10 years.
I got such a shock seeing him, he looked like an old man and the age gap was starkly apparent. All I could think was thank god I didn’t have children with him!
I think I just imagined myself at 40 as old and 60 with no real difference - old was old at 28.
There is a huge difference and my ex has now retired, his hair was white and he just hadn’t aged how I expected, he was leaving our doctors surgery with a woman about 10 years younger then him who looked thoroughly fed up with his moaning!
I am so glad I’m with someone the same age now, we both have aged in a similar way but still feel so young, we still want to travel and have adventures and 40 seems young now 😂.
Don’t be an ego boost because you deserve so much better. I felt like I was old at 30 but it really isn't I think if you meet someone your own age you'll realise that.