in any decent interpersonal relationship, you should be able to to say no and have boundaries, without there being a guilt trip or a fight.
whenever i don't want to do something but my dad wants me to, he pulls out the line "it would make me very happy if..." but what about what would make me happy? what about what I want? and how come my happiness doesn't matter and how come it doesn't matter to him? in all fairness, your happiness matters equally, but he can't get what he wants that way, so he performs the guilt trip. try not to fall for it and realize that guilt trips are wrong for him to do. he doesn't care about you, at least not as much as he should.
one time in some alternative therapy attempt, i asked the helper to yell at me and then hug me so that i might feel that if i do something wrong, it's not permanent. but she said she felt uncomfortable doing that, and i responded, "okay." suddenly, i was like "wait, that's all it takes to accepts someone's boundaries?! i just had to say "ok" and that was it?!" i didn't cross-examine her, she didn't have to justify anything, i didn't guilt-trip her, she didn't have to re-consider. all I had to do was say "ok". 1 fucking word. ever since then, i don't feel guilty when people don't accept/respect my boundaries; i get mad.
if he can't say "ok" and accept your boundary, maybe you two are not compatible. and maybe he's an asshole.
