Guys! How do I know he's serious about me...

I'm sorry it's long..

So my man and I got together.. We had been talking for a few months and then recently decided to make it official. When I first saw him I was set on him and now that we are together I'm just so afraid of losing him. He's my balance. He and I are complete opposites!

He is 24, I just turned 23. He has told me before that he hasn't been in a relationship in about 5 years. This is because he had/has some big goals he wants to accomplish. He felt as though he never had time for a relationship and he doesn't want to put that effort into something. But then he decided to get with me..

So sometimes I feel like maybe he doesn't want to be with me (he likes alone time/personal space ect.)

But when we are together he tells me I'm beautiful. He makes me feel so wanted and sexy. He makes me laugh. When I see his face after his day at work my stresses and worries of the day melt away. So I've asked him curiously why he's with me.. He tells me he's with me cause he likes me. When he looks at me sometimes I can see the adoration in his eyes.. that's something I've never seen. At least when a man looks at me. He also said that I help him see and realize, and understand things about himself that he couldn't see when he didn't have someone to care about. Before he met me he told me he was in a low place mentally..

Yesterday he told me that he got into a relationship with me because he forgot how it feels to be in a relationship. And then I asked him "so you're testing the waters?" And he said yes.. I kinda took that as like I'm just a temporary thing.. but I feel like I'm also psyching myself out. His actions and words show me he is.. but

I just tend to overthink. A lot.