The guy I'm breaking up with so I can pursue a summer job sent me $500 to cover my last few expenses I was stressing over. Do I keep it?

Title keeps it pretty point blank.
But now here is the long background-
I (F21) started seeing a E (M23) beginning of March. Probably the healthiest relationship I've ever been in, which given my age may not say much haha. He has a very quiet personality while I am very much loud and outgoing. From the start I made it very clear I did not expect him to change his personality to "keep up" with me, and I spent a lot of time learning what his boundaries are and making sure he felt comfortable communicating anything with me.
The only downsides throughout are time together were times I felt like I was being ignored if he left my message on read for more than 4 hours. I made sure to take my time to process my emotions before I brought it up to him. It took maybe three different conversations before I was able to word it in a way that he understood, and that was all it took for him to be more considerate and let me know if he wasn't going to be on his phone at certain times etc. We would hang out once or twice a week and I really enjoyed each moment.So all in all, a pretty good relationship.
Unrelated to the relationship, I personally have been unhappy with my job and feeling stuck. Hour drive there and back, and didn't have many tasks to do in the office other than be there if an email came in. Things I could have easily done at home but boss likes things on paper. Due to the drive, I only actually worked 6 hours a day. Ended up interviewing and getting an offer to work in Alaska for the summer, working easily twice as many hours making $2 more than what I do now plus tips. I want to see new places so its basically a dream come true type of offer. Everyone is very supportive of me going, including E.
However, given he and I have only been together for barely two months at the time I made the decision, I didn't think it would be fair to commit to a long distance relationship. Those have never appealed to me as I prefer to see someone in person. I don't want to have to worry about trying to keep up with someone if we are living in different worlds. From experience, no one has ever been willing to work with me on it (friends, exes)
E was very emotional but understanding, and is still being very supportive about me going to Alaska. He has never once tried to get me to promise to come back to him, or even talk to him while I'm gone.
I am an external processor, I was stressed about making ends meet this month but know I'll be more than okay next month. I don't want to put anything more on a credit card and I was talking to E about things I was trying to rearrange to stretch money.
He told me to breathe and that I'll figure it out and that everything's going to be okay.
Then E sent me $500 on zelle.
I immediately told him no. It doesn't feel right accepting money from him.
He says yes, he doesn't need the money, he has all his bills paid, is working more hours now and can easily make it back in two weeks.
E says that he knows I'm stubborn but he's not going to lay down on this one.
I told him I would feel guilty, what if I didn't come back? I don't know when I would be able to pay it back. What if we didn't keep talking and it was a waste of money?
E replied "you finding your happiness is more than worth it. I'm not doing this to ensure you come back, I'm doing this to help a friend. I don't care if I ever get it back."
Of course the money would really help me, I'm trying to prepare for things I could possibly need while I'm gone 4 months in a remote location.
I feel like its pretty cut and dry. If it were me in his shoes, I would absolutely offer money and not expect it back, no ifs or buts about it. I've given money to friends I no longer talk to and no, I don't regret it. I was their friend when they needed a friend, and we've grown in different directions.
But now I'm here. I feel guilty. Part of me is extra worried its some kind of manipulation tactic even though he has never once done anything negative or overly positive (ie lovebombing).
Maybe I'm not upset over the money, maybe I'm conflicted with my emotions for E and feel like I'm making a mistake leaving him. But got the great combo package of attachment AND commitment issues.
Do I accept the $500? Is my emotional confliction blinding me from seeing this as an offer of help from a friend?
tldr: ex sent me $500 to cover my expenses so I wouldn't stress out. Trying to decide if I accept it or not.


Source.

Give it back, that way he can't keep bringing it up saying how he helped you out after you two broke up which will be his way trying to show his next girlfriends how nice of a guy he is when in reality he's just trying to make himself look good as being a boyfriend