UK standard visit visa refused under V4.2 a) and c) & V4.3 a) and c) [duplicate]

I need help understanding what they ask of me. This is my second refusal in a month. Let me give you the background story to the whole process.

Last April 2017, after visiting Thailand with my then friend, we decided to date exclusively and for me to visit him on July that year. I applied for a UK visa and put my newly acquired boyfriend as my sponsor but stated that he was a family friend instead, as we are a homosexual couple and I was quite apprehensive that stating or labelling ourselves as a homosexual couple would hinder the chances of granting a visa. Another reason is that I had only turned 18 a few months prior to the UK visa application in 2017.

As I recall, I only submitted my school transcripts, passport copies of my own and my boyfriend's, bank statements of each of ours and his letter of invitation. I got the UK visit visa but unfortunately did not travel due to personal commitments with the University.

My first refused visa application (letter not found) mentioned I failed to meet requirements of Appendix V paragraph V4.2 a) and c) and states that I heavily relied on my sponsor (boyfriend) and did not have funds of my own as well as not providing enough ties that convince my return to the country of my residence.

Now, my boyfriend ("partner" as per application) and I are persistent that I visit him in his home in Wales from 18th July 2018 to 29th August 2018. We bought a round-trip ticket. I declared that I had GBP 1,000 in my account for my personal expenses with my bank statement as evidence, my boyfriend's willingness to pay of GBP400 for my trip and also added my mum as another payee, who woule be funding GBP 1,050 for my trip (I thought this would make a stronger base for my app.).

I declared in my application that I would be expecting to spend around GBP 500-600 in expenses (excluding the round-trip tickets back home). I mentioned that we we're on a long-distance relationship and we traveled to a country in Asia to meet instead of our own country homes).

For my accommodation, I mentioned that I would be staying at my partner/boyfriend's rented house in Wales. For my visit purpose I stated that I planned to visit a University campus as a prospect student l, as it is an associated university of the college I am currently studying in and I am able to top-up my degree to a bachelor's in this Welsh university. Another reason is the obvious visit for my partner, as we haven't seen each other in a year (duration not stated in application), as well as visit local tourist, cultural and historical attractions, and visit his friends and family.

I have submitted my previous employment contracts, and my 2 current employments (my bosses aren't keen on stating until I have to work for them, as I am employed only part-time in both establishments. They only state my starting date until PRESENT), my current payslips, my identity card that mentions permanent residency in my country of residence (other than my nationality), and birth certificate that ties me to my mum, who is also living with me, my proof of address via letters from schools and other government bodies, and a school tcertificate that states I am an enrolled student in their campus for the year 2018 - 2019. These are the documents I have submitted to prove I have ties to my country of residency and must return by the end of my trip.

What can I do to get approval on my next application? How can I prove my relationship with my boyfriend?

Please assist. Should there be any more queries or should you require further information about my application, please comment below and I will answer promptly. Your help is highly appreciated.