Most Helpful Guy
There are tons of guys who can be very nice to your p*ssy, but only a few of them will actually care for the rest of you.
For him (or any individual not having moral qualms manipulating anyone who's letting them do it), it is reasonable to fall back to you now and at any future point when he's not seeing someone else or when seeing you at the same time is not taxing them time-wise, money-wise, or emotionally.
For you, using him for sex is probably a lesser evil than multiple other partners; but if it is taxing you emotionally and adding to your "luggage", you're probably best off looking for someone genuine.
OR you can take the "he'll change for me" view, which of course no other manipulated and discarded girl ever had in the history of mankind, but that is up to you.
Most Helpful Girl
I just learned this the hard way.
When someone tells you something the first time -LISTEN TO THEM.
I just got my heart broken because I got caught up in my feelings. If he doesn't want a relationship with you by now he won't want one later. This just isn't it. He's going to use you and later on make you feel that it was your fault because he already told you he doesn't want it.
Coping and moving on is harder and I don't know what to tell you about that except you're just gonna have to go through it. I've been sad for weeks now, and avoiding men, and it would just be easier to go back but then I would be disrespecting myself. Don't do that to yourself.