Does anyone know a full-color BL manga that has jealousy or is similar to penthouse xxx? ...

Have you read Lack of Love? It's on the popular manga list~ It's got lots of jealousy and is a good read.
ヾ(❀╹◡╹)ﾉ~ If you haven't I super recommend.
http://www.mangago.zone/read-manga/lack_of_love/

Yep yep (๑•ㅂ•)و✧
http://www.mangago.zone/read-manga/if_you_hate_me_that_much/

http://www.mangago.zone/read-manga/well_done/

http://www.mangago.zone/read-manga/bj_alex/ You might have heard of it!

http://www.mangago.zone/read-manga/cover_up/

http://www.mangago.zone/read-manga/paid_fujoking/

http://www.mangago.zone/read-manga/food_chain/

http://www.mangago.zone/read-manga/hide_seek_leepado/

http://www.mangago.zone/read-manga/love_bite_lamyo/

http://www.mangago.zone/read-manga/behind_the_desk/

http://www.mangago.zone/read-manga/nightmare_building/

http://www.mangago.zone/read-manga/my_suha/

http://www.mangago.zone/read-manga/aplicaci_n_humillante/

http://www.mangago.zone/read-manga/dispar_4u/

http://www.mangago.zone/read-manga/don_t_pick_up_the_soap/

http://www.mangago.zone/read-manga/lack_of_love/

http://www.mangago.zone/read-manga/they_are_a_couple/

http://www.mangago.zone/read-manga/love_is_not_real/

http://www.mangago.zone/read-manga/anti_p_t/

http://www.mangago.zone/read-manga/in_your_eyes_down/

http://www.mangago.zone/read-manga/serene_bird/

http://www.mangago.zone/read-manga/private_lessons/

thank u

You’re welcome (⌒▽⌒)
Each one is soooo good. Be sure to add them all for future reading. Enjoy (●'◡'●)ﾉ