Why is this guy so up and down?

I need some help figuring this guy out. We have known each other for a long time and dated for a while too but he got scared of commitment. This last year has been a lot of ups and downs and i thought we had finally gotten to a good place in our friendship. Over the last few weeks he has been very attentive and we have spent a lot of time together which has been great. Now in the last week he is starting to accuse me of not being honest when I am out with a friend saying that I am on a date and I don't have to lie. I feel like I have to let him know what I am doing and with who and if I dont it usually turns into an argument. I am not sure what he wants from me and I am being very cautious because of past situations. Please help me figure out his behavior...I don't get it. I love spending time with him and when we are great we are really great but he doesnt like it when I am not available??? He is 39 and I am 33.