Hoping someone here has been through similar
In September I went on a date with this insanely handsome and wonderful guy and had an amazing time, we met up once a week for the first month and more recently been seeing him about twice a week. We are pretty mad about each other but I'm cautious about rushing things, having said that...we've both spoken about how crazy we are about other and he's said he wants nothing more than to wake up beside me everyday. I'm smitten.
So the first time we had sex, it was lovely. Pretty standard mind you but definitely lovely! The second time was bloody fantastic, we were pretty intoxicated but again really enjoyable and so much chemistry going on
The third time he initially had an erection, lost it, and nothing I did could bring it back. I figured he was a little nervous. He seemed embarrassed and kept saying sorry, these things happen-I really wasn't overly bothered.
Then last night again he had an erection, managed penetration but within a minute or so it was gone. I didn't want to do like last time and try get it back for him as that might have been pressure on him to get it back so again he apologised, I reassured him it didn't matter, I was just so happy that we were together and absolutely loved just being close to him, but he looked so sad whilst we were at it!
The thing is, he's going through hell right now. Going through horrible court proceeding with his ex wife who won't let him see his DC which is obviously crushing him. So of COURSE he's going to be tired/stressed/emotionally exhausted etc etc etc and to be honest I'm not surprised in the slightest that this is affecting him in this way!
But I've never had experience of this and not entirely sure of the best way to broach this so hopefully this is where you lot come in 
I've had some very irrational thoughts, like...he looked really sad so perhaps that's because he's not having sex with his ex wife. This stayed with me last night and I felt really sad and hurt but I know this is all in my head and not a true indication of his actual feelings! (It was probably more down to the fact that he realised he was just about to lose his erection and was trying hard not to!) Also had thoughts of I don't do anything for him, I wasn't the one who initiated it so maybe I need to be more forthcoming in my advances and maybe I just don't turn him on etc etc. Don't want to blame myself but maybe he's quite shy in the sex department (he's yet to take off my bra!) or felt under pressure to perform or perhaps I wasn't able to make him feel relaxed. The thing is....with us being so 'new' I don't actually him all that well in the grand scheme of things so have no idea of what his sex life was like before or what he's actually like in the bedroom (from the first two times I think fairly vanilla but could have a fetish or two for all I know!)
Obviously I need to talk to him but it's difficult. I don't want him to feel embarrassed or awkward, and if it is because I just didn't quite float his boat then he's not going to tell me that anyway!
The fact that it's happened twice now might have him dreading the next time incase it happens a third so do I suggest we take sex off the menu for now? Feels like this big elephant in the room now but just got a message saying he'll do whatever it takes to 'fix' what's going on inside of him so I'm sure we can resolve this but just don't know where to start tbh