Help! Partner with adult children going thru divorce

I am 35 & my new boyfriend if 4 months is 52 is currently going through a divorce. He & his wife were living in the same house, but separated for 3 years before filing for divorce about 7 months ago. She moved out, & he has just moved into a new house. He has 3 boys & they have moved with him. Their ages are 27, 24, & 21. His sons are aware he is dating, but not making it easy on him - always questioning him with where he is going & what he is doing.

The divorce will be finalised in 5 months. I do get a bit frustrated with the sutuation regarding his sons though. I understand & completely support the fact they are his kids & his priority, & he is trying to ease them into getting used to the divorce, however its frustrating as they are adults & especially the older two should not even be living with him at their age, let alone sticking their nos3s into his personal life & voicing their opinions about it. They know he is dating, but have said to him they think its too soon. Currently we cant spend time at his place because of the sons & I know he doesnt want to be too "open" about us as you never know how his ex will react either - but he did say this will all change once the divorce is finalised.

So, i am looking for any advice or thoughts on this situation - what i might expect to happen, how to handle things - both currently & things to come, & really anything else.

Thanks in advance!!