He is 7, so luckily he's still little and you have a lot of time to change his view of you/you & his Dad.
You don't want to feel like this when he's 17 and the longer it goes on, the worse it gets... but at the same time you have to take the 'long view' and not expect it to change overnight.
You don't want to feel unwanted/uncomfortable in your own home, not now and not still in 10 years time!
I am suprised that a year/2 years on he is still like this.
Do you think his Mum influences him in this?
Although you don't have a problem with him wanting it to be just him and his Dad, I think it's a bad move to give into this as otherwise you will spend the rest of his childhood 'losing' your DP every other weekend which is not on and if you have children will be horrible.
Of course it's good for him to have some time on his own with his Dad - just as it is for any child.... but not to be allowed to demand/create that situation all the time.
It is your (as in yours and DP's) home and it is up to you (both) to decide how things are in your home - it doesn't matter what they are like in his Mothers home. Different houses - different rules is something kids deal with fine.
You need to talk to DP and make him see that while his son is little is the time to discipline him. It is much harder when they become teenages and does he want an unruly teenager who is rude and getting into trouble? Of course he wants to have fun and a nice time when his son is there - but you can do that with boundaries in place.
You need to create a family where DS is a part of that, he needs to feel wanted, loved, safe etc - he does not need to feel incontrol/like it revolves around him - that wont do him any favours. So, no, spoiling his isn't doing him any favours. Whether that's allowing him to do as he pleases or with material things.