Dating in your late thirties… sucks.

Hi. I’ve recently been separated from my partner of 15 years. I’ve been out dating again and I hate it. I’m a pretty even keeled person…. But I have to be doing something wrong.
It seems like every person I actually get excited about , suddenly says they are not interested. I go back through texts and they’re all saying how much they enjoyed our dates, can’t wait to see me again and then suddenly “I met someone else I’m more into”.
I have been reflecting on this and I have to say- this is actually something that happened to me a lot when I was younger, too. There’s been one relationship I had where both of us were actually crazy about each other but because of different goals we went out separate ways (we are still good friends to this day though). I actually wasn’t really hyped up about my 15 year long relationship, I mean I love him and I found him attractive but it was almost like, two people who could stand each other and found each other attractive enough 😆 we just sort of kept dating and had a kid and he did some really stupid things and so we aren’t together anymore , We don’t hate each other , so that’s good... But anyway.. original point.
I don’t really want advice or need to hear about how it’ll all be good - I just want to know if there is anyone that’s experienced this and to just … idk let me know I’m not alone ? I feel quite sad about it . I’ve had to take a break from the dating apps because my little heart can’t take it. My old 36 year old heart haha. So much rejection, so much sort of like .. small grief over the things I thought were going to happen , etc. I’m just a little sad.