My boyfriend searched “My girlfriend doesn’t make me as happy as my ex”

I’ve never done this before so sorry if my sorry telling isn’t that great. I’ve been in a relationship with my boyfriend for almost 8 months now and while on his computer I went through us search history trying to get an idea of what he might want for Christmas and found him searching things like “how to get over the best relationship I’ve ever had” “how to to get of over someone you love” and well… the title of this post. It devastated me to see that and I’m honestly unsure if I’m better off breaking things off for good.
I don’t think I met him at a good time in his life. His ex broke up with him claiming to have lost feelings and was stringing him along for a while while she had her fun with new guys. He met me two months after the break up and wasn’t over the the break up but liked me so he didn’t want to call things off. He has a history of moving on too quick and the same thing happened with him getting into a new relationship two months after his break up. Only this time his ex was not a terrible person (so it seems) so instead of her situation where he hated his ex girlfriend. They lasted about 8 months. With my situation he missed her and still had feelings for her for the majority of our relationship. This led to frequent fights and overalls hurt me because I feel like I’m in love with someone who doesn’t love me the same. I confronted him about it and he told me he was having a hard time moving on and he didn’t really think that. But I think that’s bs. I feel like he is just with me because he doesn’t want to be alone and I’m a rebound.