Video report by ITV News Royal Editor Chris Ship
Prince Harry has said he is "taking a leap of faith" in stepping back from his life as a member of the royal family but added "there really was no other option".
Speaking to supporters of the charity Sentebale he co-founded, the Duke of Sussex said: "Before I begin, I must say I can only imagine what you may have heard and perhaps read over the past few weeks.
"So I want you to hear the truth from me as much as I can share, not as a prince or a duke but as Harry, the same person who many of you have watched grow up over the last 35 years but now with a clearer perspective.
"The UK is my home and a place that I love, that will never change. I have grown up feeling supported by so many of you and I watched as you welcomed Meghan with open arms as you saw me find the love and happiness that I had hoped for all my life.
ITV News Royal Editor Chris Ship on the couple's future finances
"Finally, the second son of Diana got hitched. Hurray."
The duke was speaking at a dinner for supporters of Sentebale – his Africa-based charity supporting youngsters with HIV – at the Ivy Chelsea Garden in London.
It comes a day after royal family talks concluded and the Sussexes announced they will stop carrying out royal duties from the spring, no longer use the title HRH and will repay the taxpayers’ millions spent on their Berkshire home.
He mentioned Meghan in his speech, adding: "I also know you’ve come to know me well enough over all these years to trust that the woman I chose as my wife upholds the same values as I do.
"And she does, and she’s the same woman I fell in love with. We both do everything we can to fly the flag and carry out our roles for this country with pride.
"Once Meghan and I were married, we were excited, we were hopeful, and we were here to serve.
"For those reasons, it brings me great sadness that it has come to this. The decision that I have made for my wife and I to step back, is not one I made lightly.
"It was so many months of talks after so many years of challenges. And I know I haven’t always gotten it right, but as far as this goes, there really was no other option.
"What I want to make clear is we’re not walking away, and we certainly aren’t walking away from you. Our hope was to continue serving the Queen, the commonwealth, and my military associations, but without public funding.
"Unfortunately, that wasn’t possible. I’ve accepted this, knowing that it doesn’t change who I am or how committed I am.
"But I hope that helps you understand what it had to come to, that I would step my family back from all I have ever known, to take a step forward into what I hope can be a more peaceful life.
"I was born into this life, and it is a great honour to serve my country and the queen. When I lost my mum 23 years ago, you took me under your wing.
"You’ve looked out for me for so long, but the media is a powerful force, and my hope is one day our collective support for each other can be more powerful because this is so much bigger than just us.
"It has been our privilege to serve you, and we will continue to lead a life of service.It has also been a privilege to meet so many of you, and to feel your excitement for our son Archie, who saw snow for the first time the other day and thought it was bloody brilliant!
"I will always have the utmost respect for my grandmother, my commander in chief, and I am incredibly grateful to her and the rest of my family, for the support they have shown Meghan and I over the last few months.
"I will continue to be the same man who holds his country dear and dedicates his life to supporting the causes, charities and military communities that are so important to me.
"Together, you have given me an education about living.
"And this role has taught me more about what is right and just than I could have ever imagined. We are taking a leap of faith - thank you for giving me the courage to take this next step."
Camilla, Duchess of Cornwall, responded "course" when asked if she will miss Prince Harry and Meghan when they step back from their lives as members of the Royal Family.
The duchess was visiting Prospect Hospice in Wroughton, Swindon in celebration of their 40th anniversary year, as their patron.
Sentebale chairman Johnny Hornby said everyone in the room was "moved" by Harry's "genuine" and "heartfelt" speech.
"I wasn't surprised that he was going to be open and heartfelt, but I certainly wasn't aware of the content of his speech before," Mr Hornby told ITV News.
In reaction to Harry's mention of Meghan and the love he feels for her, Mr Hornby said: "To anybody who spends any time with them, you can feel that sense of adoration between the two of them.
"That's as strong today, as it ever was, and he probably didn't need to say it, as everybody can see it, but I think the fact he did say it meant a lot to the people in the room and I'm sure it meant something to her too."
Prince Harry was seen arriving at the UK-African Investment Summit in London, the day after his emotional speech at the Sentebale event, as he carries out his royal duties still.
He met with Prime Minister Boris Johnson and Saadeddine Othmani, Prime Minister of Morocco, among other world leaders.
He attended the summit at the request of the UK government.
Harry’s grandmother, the Queen, issued an emotional statement on Saturday, saying she recognised the “challenges” the couple had faced over the past year.
Unusually, she used the first names of her grandson and his family in a public message.
The Queen said: “Following many months of conversations and more recent discussions, I am pleased that together we have found a constructive and supportive way forward for my grandson and his family.
“Harry, Meghan and Archie will always be much loved members of my family.”
In a wide ranging interview with ITV News Political Editor Robert Peston, former prime minister Gordon Brown said Her Majesty "does a wonderful job" and the public should "respect" her right to make her own decisions.