Is he called Danny? 😉
For the bike related clutter:
It’ll be fine so long as you accept, that is the way he is, chance is that is the way he will be.
For the dog: If you are to be the new member of the pack, then you need to establish you’re position in the pack. Till now your BF was alfa male and his mutt alfa female, or Beta male/female.
You need to dominate the mutt and put it down the order making it a gamma, unless it’s his alfa female, in which case he needs to stop sleeping with it and make it a beta female.
I’m not calling you a dog of course, but in the eyes of the mutt, you will be classed as one.
HTH