Thoughts on this?

The guy I’ve been seeing for the past few years have been acting so shady! One day I asked him to be honest with me as to if he is currently seeing other girls (I just needed to know and he said most definitely not) but I don’t know it’s just very weird. And my gut feeling says he is, but my heart says he isn’t. I just don’t know how to prove it 😓

When he comes over it’s fine, we laugh and talk etc but sometimes always on that phone of his. I kind of feel like it’s rude if he wants to hang out with me but not really giving any attention.