I also echo everyone's suggestion of 'Bpoop Phaeh Saniwaat'. It's been the hit-show in Thailand this year and so far no other thai lakorn has come close to stopping the BPS fever in Thailand right now.
Other thai lakorns with nice loving male leads to recommend are:-
1) The 'Suparburoot Juthatep' or 'Gentlemen of Juthatep' series: https://mydramalist.com/article/2014/06/22/thai-lakorns-recommendations-part-two
5 short lakorns about 5 brother's individual romances. Set in the 1950s, if you like gentleman-like period romances, this series of shows might be of great interest for you. Each brother's show also tends to focus on different themes e.g.
1st brother's is about duty/ responsibility vs love;
2nd brother's is about love across class divides;
3rd brother's is about love prevailing over logic, and about the strong have a duty to defend/ protect the weak;
4th brother's is about finding love in unexpected places;
5th brother's is about fighting for love against all odds.
2)'Oum Rak': https://mydramalist.com/10186-oum-ruk
The male lead, Chen, here is an absolute sweetheart of epic proportions. You'll be hard-pressed to find more loving, caring and adorable ML. The FL here has a completely opposite character and personality to the ML - she is sharp-tongued, aggressive and arrogant - but she softens up to an extent after a while. Some people don't really like the FL but it is undeniable that the ML is pure gold and most people watch this show for him.
3) 1st show in the Rising Sun series: https://mydramalist.com/10503-roy-ruk-hak-liam-tawan
Takeshi, the male lead, one of the descendants of a prominent mafia gang, falls head of heels in love at first sight with a girl and pursues her in a rather shy but determined way. He's a gentleman with his woo-ing, despite his mafia roots. Please just be aware though that the second female lead here is one batshit crazy girl, and the villains can also be rather cartoon-ish. Typical thai lakorn formula.
4) 'Soot Saneha': https://mydramalist.com/10188-soot-sanaeha
Same actor/ actress pairing as 'Oum Rak', if you like this pair. The ML here has a rather firm character but he's caring and kind all the same. The FL is less abrasive than her character in 'Oum Rak', and these 2 make a great drama couple in this show. This show does have your Thai lakorn tropes again of bitchy second FL, cartoony villains and crazy side characters but the main couple are golden.
5) Part 5 of the Cupid series: https://mydramalist.com/22637-the-cupids-series-sorn-ruk-kammathep
Another case of opposites attract, the FL is one manly, tomboyish female while the ML is your smiling gentleman hero. Lots of humour and laughs in this show but again, not exempt from your thai lakorn tropes of interfering second leads, villains and side plots/ characters. You'll need to get used to these sort of things when watching thai lakorns in general.
Hope this list has been helpful, and enjoy your thai lakorn journey!