Boyfriend size issues

Hi uh, recently I entered a relationship with some dude I've known for a little while and we decided we'd give it a go The only problem is, I'm not sexually experienced whereas he's a lot more experienced than I The dilemma I'm having is that he's rather on the large side, length and girth wise. I haven't really done much in terms of exercising 'down there' because I didn't feel it was necessary till now I know there are other ways to please one another but I'd really like to give it a go with this dude as I really like him. Basically, I'm just wondering if anybody else has encountered issues such as this in the past and if they have any guidance as to what I should do to make myself a little more comfortable and not experience pain because of his size I'm aware of the fact that bottoming is often accompanied by a little bit of pain when you haven't done it much before but uh I'd greatly appreciate a little bit of reassurance Thank you! : )edit: We've actually discussed this in the past and he's aware of the fact that there may be some difficulty to start off with but I was just hoping I could do something myself. I was thinking about those uh...butt training sets but I'm not too sure