SO issues - help me :(

I'm 23. Relatively attractive. Blonde. Have big boobs. 5ft1. Not a stick figure but not fat. Have a great smile which is my greatest asset and generally love life. And my bf doesn't really want to have sex with me or do anything new and exciting in life. 

He's 36. Relatively attractive. Bald (but in a good way!! He has a great facial hair). He has a beer belly 'dad bod' and is  6ft4 - rather tall! He would rather sit at home, drink fizzy, eat chips and watch a movie than do pretty much anything else. Including sex. 

We've been together for 1.5yrs. I moved countries for him. He really swept me off my feet. He gave me the most amazing love story to tell but now reality has set in. 

Is he just old!? There's a 13 yr age gap between us so I knew this would always have to be something we would need to consider. He's never thought of it as an issue which is ridiculous, because it is.

We had loads of sex in the beginning. It was the best sex I'd ever had. He was the first guy to make me cum by going down on me. #nightillneverforget.  Hahaha. 

He's always given off this confident exterior like he's in control and knows what he's doing but as of recently, he's done a 360. We  got to the point where we were having sex once every 2 weeks compared to every 2 nights. He wasn't cuming at all which made me feel awful. And when he did on the odd occasion, it was while I was going down on him. 

We talked about it because I was worried that he couldn't cum. He said that's just how he is and made me believe it was ok and nothing that I was doing. I asked him to tell me or show him how to make him cum quicker but he always said 'every thing you do is great'. All I friggen do is blow him because normal sex doesn't do much for him which is why I blow him. 

But now he barely cums from even that!! Is this an age thing and should he get it checked out if it's putting stress on our relationship? 

Oh and also - I did catch him watching a lot of porn during the hardest part of our relationship where we weren't being intimate at all. And that was from him saying no, not me. I gave him a chance to explain and he said it was because he was looking for new positions..... I let it slide and figured he would up his game and make love to me more. Unfortunately not. 

We hit another low. This time I was the naughty gf and looked at his history. But I just knew he was still looking at porn and not having sex with me and this was my way of confirming my gut instincts are correct. 

This also coincided with the time I promised him I would tell him the truth about my feelings and when I'm upset etc because usually I'm one to keep quiet. 

So I confronted him about the porn thing again. The porn he had been watching was MILF porn. The complete and utter opposite to what I am. And this time he 100% completely denied it and blamed it on pop ups. Not only did that hurt me, but the fact it was milf porn. This has really F%^ked me over. 

I've been trying really hard to forgive him.. But every time we have sex, I just think he's only having it with me to keep me happy. And he's probably going to wank off to Milfs tomorrow once I've gone to work because he can't cum with me. 

Not only is the sex thing an issue, but he won't even come to the beach wth me, go for a walk with me or do anything new and exciting. A big part of me believes he's just lazy and stuck in his ways because perhaps it's easier to watch porn than get all sweaty and hot doing it. I basically have to beg him to take me from behind.... 

I understand he may have body confidence issues that perhaps effect his confidence in the bedroom, but he's the one who's taught me that it doesn't matter what other people think, as long as you and your SO are together and happy. And I was. And maybe he's unfit and might get a little puffed going for a walk, but so would I! And maybe he might be concious of his 'dad bod' at the beach, but I'm no size 8 with a flat stomach. But he's the one who's given me the confidence to love myself and go out and do new stuff. But it's like I've taken his confidence and left him with nothing. It makes me so sad because I want to have incredible sex again, I want to see the world. I just simply want to swim in the ocean song side him. But he won't. 

What do I do... What do I ask.... Please help 

Mary X