Tired of being the 'every other weekend' girlfriend

When we've discussed his previous marriage (to a lady that I like and get on with, who has been nothing but welcoming), he doesn't really have too much insight, but I imagine they split for the reasons I'm discovering now: that he was always away driving and she was left bringing up two children during the week and holding down a job etc. It can't have been easy.
He is extremely likeable and his current boss thinks he's brilliant but he's on a different path I feel. I'm setting greater expectations for my life and he won't ever feel he can keep up.
I've stopped talking about plans and money because he gets really defensive so I may need to just be really truthful and kind and say it's not going to work.

I've been in this position. For some people, relationships are a part-time thing and just aren't their priority. Not all relationships end in being full on and committed. If that's what you want and not what he wants, maybe you're just not compatible.

If on the other hand, he's just not that experienced with relationships, maybe a talk about how you move forward to being more full-time might help?

Indifference is a killer to relationship's tho, so if you're at that point, it might be over.

Mid forties

He has started retaking a GCSE so he can be more employable

How old are you both?

To give a bit more information, he was working in North Wales, driving up there on Sunday evening to start early Monday, then coming back Friday evening. He literally had nowhere to live as he slept out in the lorry! I complained and he found a job back in our hometown, which is an hour's drive from my current home (I moved counties twenty years ago) so at least he had a base at his mum's to study for qualifications and have more evenings. He has started retaking a GCSE so he can be more employable and he isn't religious like his mum. But I don't know. I feel like there just isn't enough oomph under this man.
He's finally settled his divorce and has money enough in the bank for a house deposit but he complains that his current salary won't cover mortgage repayments and he won't pursue shared ownership properties (which are still something in this unaffordable day and age as you are still contributing to a mortgage on a house that's likely to go up in value).
He's had two years to sort things out.
In that time, I was made redundant and walked into a new job the following Monday, have gained two professional qualifications, bought a new house, landscaped a garden and have recently taken on an allotment. I do feel like I'm carrying this person, even though we don't share any finances or commitments.
His children are lovely, which is a huge bonus but I'm nervous about hurting their feelings by getting too close when I'm so undecided myself.

A red flag I see is an adult man following his mother's religious rules - does it mean he is also that religious or doesn't want to offend her?

He also doesn't want to move out.
How long has he been living here?

He also complains about his job but does nothing to change it, so I guess he doesn't hate it that much

This relationship doesn't work for you and it is ok! Break it off and look for a more compatible match

Your partner sounds very set in his ways and dare I say boring. Going for a walk a meal and drink is a nice way to spend time together. Having a meal cooked is nice but sitting there with four cans sounds like being with the lads. There is nothing wrong with that but your time is limited together. He is busy and only sees you every fortnight then goes asleep in your company. He wants to go cycling has he got the energy for that and does it interest you? discuss what you want to do. You need to make the most of your time together. It does sound like you need to talk obviously hints are not getting through.

Just be kindly honest. Tell him you are not enjoying the way things are and feel you both need to move on.

Sounds as if you've gone off him because he doesn't fit your requirements. So tell him the relationship's over.